Flip the client to region-key resolution + region names in the dossier (v0.19 P1 of #16)

- src/lib/regions.ts (new): cached, turf-free same-origin fetches of
  /region-keys.json (feature id -> key) and /regions.geo.json (id -> name) so
  WorldMap and NationPanel share one fetch each.
- WorldMap.tsx: stamps each feature's properties.regionKey (from the manifest,
  by its stable id) and resolves owner / flash / hover / click from that key via
  the shared mapFeatureOwner; the per-region flash lights the exact sub-region
  whose owner changed; click carries only the sub-region name.
- NationPanel.tsx: territory chips show the region's human name (falling back
  to the raw key) with the key in the title / data-attr.
- App.tsx: the selected-region dossier label drops the now-unused parent code.

src/App.tsx

@@ -591,12 +591,11 @@ function GameScreen({
   const [viewingId, setViewingId] = useState(game.playerNationId);
   // When the dossier target was set by a map click, remember which sub-region
   // was clicked, for a small label in the dossier. The label shows only the
-  // region's name — the static parent-country code (which never updates on a
-  // transfer) is no longer displayed, though the info object still carries it.
-  // Cleared when the user picks a nation via the manual Inspect select.
-  const [selectedRegion, setSelectedRegion] = useState<{ parent?: string; name?: string } | null>(null);
+  // region's name. Cleared when the user picks a nation via the manual Inspect
+  // select.
+  const [selectedRegion, setSelectedRegion] = useState<{ name?: string } | null>(null);
   const focusNation = useCallback(
-    (id: string, info?: { parent?: string; name?: string }) => {
+    (id: string, info?: { name?: string }) => {
       setViewingId(id);
       setSelectedRegion(info ?? null);
     },

src/components/NationPanel.tsx

@@ -1,8 +1,10 @@
+import { useEffect, useState } from 'react';
 import { Badge } from './ui/badge';
 import { Card, CardContent, CardDescription, CardHeader, CardTitle } from './ui/card';
 import StatBar from './StatBar';
 import { nationColor } from '@shared/protocol';
 import { RELATION_COLORS } from '@/lib/colors';
+import { keyToName } from '@/lib/regions';
 import type { Nation, RelationStatus } from '@shared/types';
 
 /** Human labels for a diplomatic status (the raw value is kept in data-attrs). */
@@ -38,6 +40,23 @@ export default function NationPanel({ nation, nations, isPlayer, inWindow = fals
   const relations = Object.entries(nation.relations).sort(([a], [b]) => a.localeCompare(b));
   const regions = nation.territory;
 
+  // Human region names for the territory chips (region key -> name), loaded once
+  // (cached in @/lib/regions). A key with no known name falls back to the raw key.
+  const [keyNames, setKeyNames] = useState<Record<string, string>>({});
+  useEffect(() => {
+    let cancelled = false;
+    keyToName()
+      .then((m) => {
+        if (!cancelled) setKeyNames(m);
+      })
+      .catch(() => {
+        /* names are cosmetic — a failed fetch just leaves the raw keys */
+      });
+    return () => {
+      cancelled = true;
+    };
+  }, []);
+
   const identity = (
     <div className="flex items-center gap-3">
       <span
@@ -95,15 +114,20 @@ export default function NationPanel({ nation, nations, isPlayer, inWindow = fals
         </h3>
         {regions.length > 0 ? (
           <div className="flex flex-wrap gap-1.5">
-            {regions.map((code) => (
+            {regions.map((key) => {
+              const label = keyNames[key] ?? key;
+              return (
                 <span
-                key={code}
-                className="rounded border px-1.5 py-0.5 text-xs tabular-nums"
+                  key={key}
+                  className="rounded border px-1.5 py-0.5 text-xs"
                   style={{ borderColor: `${color}66`, color, background: `${color}12` }}
+                  title={key}
+                  data-region-key={key}
                 >
-                {code}
+                  {label}
                 </span>
-            ))}
+              );
+            })}
           </div>
         ) : (
           <p className="text-sm text-muted-foreground">No territory.</p>

src/components/WorldMap.tsx

@@ -11,6 +11,7 @@ maplibregl.setWorkerUrl(workerUrl);
 import { mapFeatureOwner, type RegionMap, type RegionOwner } from '@shared/protocol';
 import type { Nation } from '@shared/types';
 import { cn } from '@/lib/utils';
+import { idToKey } from '@/lib/regions';
 
 // Minimal GeoJSON types (avoids a hard @types/geojson dependency). The choropleth
 // source is the sub-national `regions.geo.json`: each feature is a sub-region with
@@ -101,26 +102,32 @@ function cameraForPreset(presetId: string): { center: [number, number]; zoom: nu
 
 /**
  * Stamp the current ownership + colors onto a clone of the sub-national base geo.
- * Ownership and the LLM stay at **country** granularity (#16, PR 2): a nation
- * owns whole countries, so every sub-region of a country shares that country's
- * owning nation's color — the map looks like the old country choropleth, but
- * subdivided into finer cells. Each sub-region therefore carries:
+ * Ownership is at **region-key** granularity (v0.19, #16 P1): each sub-region has
+ * its own region key (from `public/region-keys.json`, looked up by the feature's
+ * stable id) and the RegionMap is keyed by that region key, so a single
+ * sub-region can change owner while its neighbours keep theirs. Each feature
+ * therefore carries:
  *
  *  - `regionId`  – its own sub-region id (e.g. `FRA-03`), kept in a property that
  *                  survives into the features MapLibre hands back on click/hover
  *                  (the top-level `id` is repacked into a numeric index, #6);
- *  - `parent`    – the parent country's ISO_A3 (e.g. `FRA`), the RegionMap key;
- *  - `fill`      – the owning nation's stable color (from `RegionMap[parent]`);
- *  - `owner`/`ownerId` – that nation's name/id (empty for an unowned country);
+ *  - `regionKey` – the region key (e.g. `moselle-rygy`), the RegionMap key;
+ *  - `fill`      – the owning nation's stable color (from `RegionMap[regionKey]`);
+ *  - `owner`/`ownerId` – that nation's name/id (empty for an unowned region);
  *  - `stroke`    – a per-border alpha (owned brighter than unowned);
  *  - `isPlayer`  – 1 when the owning nation is the player (drives the amber
  *                  player-highlight border).
  *
- * Crucially, the owner lookup keys the RegionMap by `properties.parent` (the
- * country ISO_A3), **never** by the sub-region id — the RegionMap has no
- * `FRA-03` entries, only `FRA`.
+ * Crucially, the owner lookup keys the RegionMap by the stamped
+ * `properties.regionKey`, **never** by the sub-region id or the repacked
+ * top-level `id` — the RegionMap has no `FRA-03` entries, only region keys.
  */
-function applyRegions(geo: FeatureCollection, regions: RegionMap, playerNationId: string): FeatureCollection {
+function applyRegions(
+  geo: FeatureCollection,
+  regions: RegionMap,
+  playerNationId: string,
+  idKey: Record<string, string>,
+): FeatureCollection {
   const out: FeatureCollection = JSON.parse(JSON.stringify(geo));
   for (const f of out.features) {
     f.properties = f.properties ?? {};
@@ -128,11 +135,11 @@ function applyRegions(geo: FeatureCollection, regions: RegionMap, playerNationId
     // survives into the rendered features (the top-level `id` gets repacked).
     const subId = f.id == null ? '' : String(f.id);
     f.properties.regionId = subId;
-    // Ownership lives at the parent country: resolve `properties.parent`
-    // (the ISO_A3) against the RegionMap. Never the sub-region id.
-    const parent = typeof f.properties.parent === 'string' ? f.properties.parent : '';
-    f.properties.parent = parent;
-    const r = parent ? regions[parent] : undefined;
+    // Resolve this feature's **region key** from the manifest (id -> key) and
+    // key the RegionMap by it — never the sub-region id or the repacked id.
+    const key = idKey[subId] ?? '';
+    f.properties.regionKey = key;
+    const r = key ? regions[key] : undefined;
     if (r) {
       f.properties.fill = r.color;
       f.properties.owner = r.owner;
@@ -151,16 +158,21 @@ function applyRegions(geo: FeatureCollection, regions: RegionMap, playerNationId
 }
 
 /**
- * Build a FeatureCollection of just the sub-regions whose **parent** country is
- * in `parents` (cloned). Used by the territory-change flash: a turn changes a
- * whole *country* (the RegionMap is ISO_A3-keyed), so a changed country's code
- * must light up **all** of its sub-regions, not a single feature.
+ * Build a FeatureCollection of just the sub-regions whose **region key** is in
+ * `keys` (cloned). Used by the territory-change flash: a turn can change
+ * individual sub-regions (the RegionMap is region-keyed, v0.19 #16 P1), so each
+ * changed region key lights up exactly the sub-region that owns it.
  */
-function featuresByParents(geo: FeatureCollection, parents: Iterable<string>): FeatureCollection {
-  const set = new Set(parents);
+function featuresByRegionKeys(
+  geo: FeatureCollection,
+  keys: Iterable<string>,
+  idKey: Record<string, string>,
+): FeatureCollection {
+  const set = new Set(keys);
   const features = geo.features.filter((f) => {
-    const parent = f.properties?.parent;
-    return typeof parent === 'string' && set.has(parent);
+    const id = f.id == null ? '' : String(f.id);
+    const key = idKey[id] ?? '';
+    return key !== '' && set.has(key);
   });
   return { type: 'FeatureCollection', features: JSON.parse(JSON.stringify(features)) };
 }
@@ -203,37 +215,36 @@ interface Props {
   className?: string;
   /**
    * Called with a region's owning-nation id when a sub-region is clicked, so the
-   * dossier switches to that nation. For a sub-region, the owner is the parent
-   * country's owning nation. The optional `info` carries the clicked sub-region's
-   * own id/name and its parent country's ISO_A3, for a small "which region" label
-   * in the dossier. Not called for unowned regions (the dossier keeps its
-   * current target). See the component doc for the full behavior.
+   * dossier switches to that nation. The optional `info` carries the clicked
+   * sub-region's name, for a small "which region" label in the dossier. Not
+   * called for unowned regions (the dossier keeps its current target). See the
+   * component doc for the full behavior.
    */
-  onFocusNation?: (id: string, info?: { parent?: string; name?: string }) => void;
+  onFocusNation?: (id: string, info?: { name?: string }) => void;
 }
 
 /**
  * World basemap (MapLibre GL) + a **sub-national** choropleth. The map renders
  * the finer `regions.geo.json` dataset: each country is subdivided into
  * ~100–200 km sub-regions, drawn as a finer choropleth with thin internal border
- * lines. Ownership and the LLM stay at **country** granularity (#16, PR 2): a
- * nation owns whole countries, so all of a country's sub-regions share that
- * country's owning-nation color. Rendered as a fixed, full-viewport background
- * layer (z-0) behind the floating HUD windows: a dark-navy basemap with subtle
- * terrain, per-nation stable fills (uniform per country, the choropleth is the
- * star), thin sub-region borders, a brighter/thicker amber border for the
- * player's countries, a hover tooltip (sub-region name + current owner
- * + key stats), a **click that switches the dossier to the sub-region's parent
- * country's owning nation** (no popup — see #7), a transient flash when a
- * country's owner changes (lighting up all its sub-regions), and a per-scenario
- * initial camera.
+ * lines. Ownership is at **region-key** granularity (v0.19, #16 P1): each
+ * sub-region has its own region key (from `public/region-keys.json`, looked up
+ * by the feature's stable id) and the RegionMap is keyed by that key, so a
+ * single sub-region can change owner independently of its neighbours. Rendered
+ * as a fixed, full-viewport background layer (z-0) behind the floating HUD
+ * windows: a dark-navy basemap with subtle terrain, per-nation stable fills,
+ * thin sub-region borders, a brighter/thicker amber border for the player's
+ * regions, a hover tooltip (sub-region name + current owner + key stats), a
+ * **click that switches the dossier to the sub-region's owning nation** (no
+ * popup — see #7), a transient flash when a sub-region's owner changes, and a
+ * per-scenario initial camera.
  *
  * Ownership for a hovered/clicked sub-region is resolved from the authoritative
- * RegionMap by its **parent country's** ISO_A3 code (`properties.parent`, via
+ * RegionMap by its stamped **region key** (`properties.regionKey`, via
  * `mapFeatureOwner` in @shared/protocol) — never from the feature's top-level
  * `id` (MapLibre repacks it into a numeric index at interaction time, #6) and
- * never from the sub-region id (not a RegionMap key). Unowned countries (no
- * RegionMap entry for the parent) simply do not change the dossier.
+ * never from the raw sub-region id (not a RegionMap key). Unowned sub-regions
+ * (no RegionMap entry for their key) simply do not change the dossier.
  *
  * Zoom and pan are driven directly by the user (MapLibre wheel/trackpad + drag)
  * — no floating control and no external API.
@@ -249,6 +260,9 @@ export default function WorldMap({
   const containerRef = useRef<HTMLDivElement>(null);
   const mapRef = useRef<maplibregl.Map | null>(null);
   const baseGeoRef = useRef<FeatureCollection | null>(null);
+  // The region-key manifest (feature id -> region key), loaded once; used to
+  // stamp each feature's region key and to expand the flash to its sub-region.
+  const idKeyRef = useRef<Record<string, string> | null>(null);
   // Latest props, so the mount effect's (re)establish closure always sees them.
   const regionsRef = useRef(regions);
   const nationsRef = useRef(nations);
@@ -304,17 +318,28 @@ export default function WorldMap({
               return g;
             });
 
+    // The region-key manifest (feature id -> region key), fetched once and
+    // cached in a ref so both the paint path and the flash can resolve keys.
+    const loadIdKey = (): Promise<Record<string, string>> =>
+      idKeyRef.current
+        ? Promise.resolve(idKeyRef.current)
+        : idToKey().then((k) => {
+            idKeyRef.current = k;
+            return k;
+          });
+
     const emptyFC = (): FeatureCollection => ({ type: 'FeatureCollection', features: [] });
 
     // Transient flash: pulse a bright outline over the changed regions, then fade
     // to zero over a few seconds and self-clean. Idempotent per call. `codes` are
-    // parent-country ISO_A3 codes (a turn changes whole countries); each lights
-    // up all of that country's sub-regions.
+    // region keys (a turn can change individual sub-regions, v0.19 #16 P1); each
+    // lights up exactly the sub-region that owns that key.
     function animateFlash(codes: string[]) {
       const geo = baseGeoRef.current;
+      const idKey = idKeyRef.current;
       const src = map.getSource(FLASH_SOURCE) as GeoSource | undefined;
-      if (!geo || !src || cancelled) return;
-      src.setData(featuresByParents(geo, codes));
+      if (!geo || !idKey || !src || cancelled) return;
+      src.setData(featuresByRegionKeys(geo, codes, idKey));
       if (!map.getLayer(FLASH_LINE)) {
         // Defensive re-add (normally created by ensureLayers). Keep it beneath the
         // hover highlight when that layer exists; otherwise just append.
@@ -350,9 +375,9 @@ export default function WorldMap({
     // The sub-region a hovered/clicked feature belongs to is identified by its
     // stable sub-region id in `properties.regionId` (stamped by `applyRegions`),
     // and its **owner** is resolved from the authoritative RegionMap via the
-    // feature's `properties.parent` (the parent country's ISO_A3) through
+    // feature's stamped `properties.regionKey` through
     // `mapFeatureOwner` — never from the repacked top-level `id` (a numeric
-    // index, #6) and never from the sub-region id (not a RegionMap key).
+    // index, #6) and never from the raw sub-region id (not a RegionMap key).
     const onHover = (e: maplibregl.MapLayerMouseEvent) => {
       const f = e.features?.[0];
       if (!f) return;
@@ -386,23 +411,19 @@ export default function WorldMap({
     };
 
     // #7: a click does NOT open a popup — it switches the dossier to the region's
-    // owning nation. For a sub-region, the owner is the **parent country's**
-    // owning nation, resolved from `properties.parent` (the ISO_A3) via the
-    // RegionMap (never the repacked top-level `f.id`, #6, and never the
-    // sub-region id). A sub-region whose parent country has no owner leaves the
-    // current dossier target unchanged — never a broken dossier.
+    // owning nation, resolved from the feature's stamped `properties.regionKey`
+    // via the RegionMap (never the repacked top-level `f.id`, #6, and never the
+    // raw sub-region id). A sub-region whose key has no owner leaves the current
+    // dossier target unchanged — never a broken dossier.
     const onClick = (e: maplibregl.MapLayerMouseEvent) => {
       const f = e.features?.[0];
       if (!f) return;
       const region = mapFeatureOwner(regionsRef.current, f);
       if (!region?.ownerId) return;
-      // Carry the clicked sub-region's identity (own id/name + parent ISO_A3) so
-      // the dossier can show which region was selected.
-      const p = f.properties as { regionId?: string; parent?: string; name?: string };
-      const info = {
-        parent: typeof p?.parent === 'string' ? p.parent : undefined,
-        name: typeof p?.name === 'string' ? p.name : undefined,
-      };
+      // Carry the clicked sub-region's name so the dossier can show which region
+      // was selected.
+      const p = f.properties as { name?: string };
+      const info = { name: typeof p?.name === 'string' ? p.name : undefined };
       onFocusNationRef.current?.(region.ownerId, info);
     };
 
@@ -430,34 +451,40 @@ export default function WorldMap({
       }
     };
 
-    // Stamp ownership + colors onto the regions source (no-op until geo loads).
+    // Stamp ownership + colors onto the regions source (no-op until both the
+    // base geo and the region-key manifest are loaded).
     const paintRegions = () => {
       const geo = baseGeoRef.current;
+      const idKey = idKeyRef.current;
       const src = map.getSource(REGIONS_SOURCE) as GeoSource | undefined;
-      if (!geo || !src) return;
-      src.setData(applyRegions(geo, regionsRef.current, playerRef.current));
+      if (!geo || !idKey || !src) return;
+      src.setData(applyRegions(geo, regionsRef.current, playerRef.current, idKey));
     };
 
     const ensureLayers = async () => {
       if (cancelled) return;
       ensureSources();
-      if (baseGeoRef.current) {
-        paintRegions();
-      } else {
+      if (!baseGeoRef.current) {
         try {
           await loadGeo();
         } catch (err) {
           console.error('failed to load regions geojson', err);
         }
+      }
+      if (!idKeyRef.current) {
+        try {
+          await loadIdKey();
+        } catch (err) {
+          console.error('failed to load region keys', err);
+        }
+      }
       if (cancelled) return;
       paintRegions();
-      }
       if (!map.getLayer(FILL_LAYER)) {
         // The choropleth is the star: a high opacity so the vivid per-nation
         // colors read clearly even on the dark background / over the terrain.
-        // Every sub-region carries its parent country's owner color, so a whole
-        // country reads as one uniform fill — same as the old country map, but
-        // subdivided.
+        // Each sub-region carries its own owning nation's color (v0.19 #16 P1),
+        // so the fill traces region-key ownership, not country borders.
         map.addLayer({
           id: FILL_LAYER,
           type: 'fill',
@@ -537,28 +564,30 @@ export default function WorldMap({
     };
   }, []);
 
-  // Re-color the choropleth whenever ownership changes, and flash any country
-  // (all of its sub-regions) whose owner changed since the last update (a
-  // transient, self-cleaning pulse). The diff is over the ISO_A3-keyed RegionMap;
-  // `animateFlash` expands each changed country to every one of its sub-regions.
+  // Re-color the choropleth whenever ownership changes, and flash each
+  // sub-region whose owner changed since the last update (a transient,
+  // self-cleaning pulse). The diff is over the region-keyed RegionMap (v0.19
+  // #16 P1); `animateFlash` lights up exactly the sub-region for each changed
+  // key.
   useEffect(() => {
     const map = mapRef.current;
     const geo = baseGeoRef.current;
+    const idKey = idKeyRef.current;
     const cur = regions;
     const prev = prevRegionsRef.current;
     prevRegionsRef.current = cur;
     const wasPrimed = primedRef.current;
     if (Object.keys(cur).length > 0) primedRef.current = true;
 
-    if (map && geo) {
+    if (map && geo && idKey) {
       const src = map.getSource(REGIONS_SOURCE) as GeoSource | undefined;
-      if (src) void src.setData(applyRegions(geo, cur, playerNationId));
+      if (src) void src.setData(applyRegions(geo, cur, playerNationId, idKey));
     }
 
-    if (wasPrimed && prev) {
+    if (wasPrimed && prev && idKey) {
       const changed = new Set<string>();
-      for (const code of new Set([...Object.keys(prev), ...Object.keys(cur)])) {
-        if ((prev[code]?.ownerId ?? '') !== (cur[code]?.ownerId ?? '')) changed.add(code);
+      for (const key of new Set([...Object.keys(prev), ...Object.keys(cur)])) {
+        if ((prev[key]?.ownerId ?? '') !== (cur[key]?.ownerId ?? '')) changed.add(key);
       }
       if (changed.size > 0) flashApiRef.current?.([...changed]);
     }

src/lib/regions.ts

@@ -0,0 +1,46 @@
+// Client-side region-key data access. Fetches the two static JSON files served
+// from public/ and builds the lookups the region-level UI needs:
+//   - idToKey():   feature id -> region key (to stamp each map feature + resolve owner)
+//   - keyToName(): region key -> human name (to show region names in the dossier)
+// Each is fetched once and cached (Promise singleton) so WorldMap and NationPanel
+// share a single fetch. Same-origin relative URLs (proxy/Traefik safe) — never a
+// hardcoded origin.
+type GeoLike = {
+  features?: Array<{ id?: string | number; properties?: { name?: string } }>;
+};
+
+let idKeyPromise: Promise<Record<string, string>> | null = null;
+let keyNamePromise: Promise<Record<string, string>> | null = null;
+
+async function fetchJson<T>(url: string): Promise<T> {
+  const r = await fetch(url);
+  if (!r.ok) throw new Error(`${url} → HTTP ${r.status}`);
+  return (await r.json()) as T;
+}
+
+/** feature id (from regions.geo.json) -> region key (from region-keys.json). */
+export function idToKey(): Promise<Record<string, string>> {
+  idKeyPromise ??= fetchJson<Record<string, string>>('/region-keys.json');
+  return idKeyPromise;
+}
+
+/**
+ * region key -> human region name. Built by joining region-keys.json (id -> key)
+ * with regions.geo.json (id -> properties.name). A key with no known name is
+ * simply absent (callers fall back to the raw key).
+ */
+export function keyToName(): Promise<Record<string, string>> {
+  keyNamePromise ??= Promise.all([idToKey(), fetchJson<GeoLike>('/regions.geo.json')]).then(
+    ([keys, geo]) => {
+      const out: Record<string, string> = {};
+      for (const f of geo.features ?? []) {
+        const id = f.id == null ? '' : String(f.id);
+        const key = keys[id];
+        const name = f.properties?.name;
+        if (key && typeof name === 'string') out[key] = name;
+      }
+      return out;
+    },
+  );
+  return keyNamePromise;
+}