Add favicon: white airplane on pastel blue as app/icon.svg (ISS-122)

CHANGELOG.md

@@ -1,5 +1,9 @@
 # Changelog
 
+## v0.55.0 — 2026-09-22 15:38
+- **Favicon (ISS-122).** The app shipped with no favicon at all (`app/layout.tsx` set only title/description; no `app/icon.svg`, no `public/favicon.ico`). New hand-written single-file `app/icon.svg` — a bold white top-down airplane silhouette (fuselage + swept wings + tail, one straight-line path) on a pastel blue (#93c5fd) rounded square, 64×64 viewBox. Next App Router's file convention auto-serves it at `/icon.svg` and injects `<link rel="icon">` into the head; no layout/metadata changes needed.
+- **Tests.** E2E +1 in `e2e/panes.spec.ts`: page load asserts exactly one `head link[rel~="icon"]` pointing at `/icon.svg`, and a direct `GET /icon.svg` returns 200 with content-type `image/svg+xml`. No unit test — static asset.
+
 ## v0.54.0 — 2026-09-22 15:20
 - **Long priority jobs are now always finishable (ISS-119).** `generatePackage` in `lib/game/seed.ts` drew a flat 6–72 h expiry window (priority ×0.5 → 3–36 h) independent of leg distance, so some jobs' deadlines were shorter than the flight itself and could never be completed (legs go up to MAX_JOB_LEG_KM = 9000 km; the fastest catalog plane is ~920 km/h ≈ 10 h for a max leg). The drawn window is now clamped UP after special scaling: deadline ≥ now + `travelDurationMs(legKm, FASTEST_CATALOG_SPEED_KMH)` + `EXPIRY_BUFFER_MS` (flat 1 h), reusing the existing `travelDurationMs` from `lib/sim/movement.ts`. New constant `FASTEST_CATALOG_SPEED_KMH` in `lib/game/catalog.ts` — data-driven max of `PLANE_TYPES` speeds, so a job must be finishable with the best available aircraft (NOT the starter's 510 km/h, which would wreck long-job economics); adding a faster plane tightens the floor automatically. `EXPIRY_BUFFER_MS` lives next to the deadline tunables in seed.ts. The window is a single uniform draw, so clamping up covers both requirements: short legs (drawn × scale already above the floor) are byte-identical to before, and when the raw draw falls below the floor the deadline lands exactly on it — which stays ≤ the scaled ceiling for any pair of airports on Earth (max leg ~20000 km → floor ≈ 22.8 h < the 36 h priority ceiling), so no separate ceiling raise is needed. Forced `deadlineOffsetMs` skips the floor, same as it skips special scaling (the e2e expiry hook keeps working).
 - **Tests.** Unit +5 in `lib/game/seed.test.ts` (new "expiry floor" block): pins the constants (fastest = max of catalog speeds and > starter speed; buffer exactly 1 h); a seeded sweep over 200 unforced packages on the real dataset asserting deadline ≥ now + travel time at max speed + buffer for every one (specials roll naturally, ~15% priority); the farthest within-cap pair in the real dataset (~9000 km) forced with both `priority` and null across 50 seeds each — invariant holds everywhere AND at least one package per special lands exactly on the floor (deterministic for fixed seeds, proving the clamp engages rather than holding vacuously); short legs (EDDF→EHAM ≈ 370 km → floor ≈ 1.4 h < the priority minimum window) pinned byte-identical to a replay of the pre-v0.54.0 draw order (no economy regression); forced deadline offsets still skip the floor. E2E +1 in `e2e/expiry.spec.ts`: the EXISTING `POST /api/test/create-package` hook forces EDDB→KSMF (~9000 km, at MAX_JOB_LEG_KM) with `special: 'priority'`; 10 packages are created and every one asserted to expire ≥ travel time at max speed + buffer after creation (and ≤ the 36 h priority ceiling), then all ignored for cleanup — no new server hooks.