feat(#46 PR 2): per-region stat lever (regionChanges) + region-stat hover

v0.29.0 — the LLM can now target individual regions' stats via
TurnResult.regionChanges (set/add per stat, clamped 0-100), applied
after nation-wide stateChanges and before the weighted-median
recompute. The map hover tooltip shows each region's own four stats.
The stub stays deterministic (regionChanges: []).

Fixes #46 (PR 2 of 2)

src/App.tsx

@@ -707,6 +707,7 @@ function GameScreen({
         presetId={game.presetId}
         unowned={game.unowned ?? []}
         markers={game.markers ?? []}
+        regionStats={game.regionStats ?? {}}
         onFocusNation={focusNation}
       />