[AZ-450] [AZ-451] [AZ-452] [AZ-454] Externalize URLs + accessors

Refactor batch 1 of 2 for the 01-testability-refactoring epic
(AZ-447). Minimal-surgical edits to make the UI's external
dependencies overridable for the test profiles in
_docs/02_document/tests/environment.md.

- AZ-450 (C03): tile URLs externalized to VITE_OSM_TILE_URL and
  VITE_ESRI_TILE_URL with the production strings as defaults.
  Fixes the AC-N3 / NFT-RES-03 air-gap regression and lets the
  e2e profile's tile-stub serve tiles deterministically.
- AZ-451 (C04): Leaflet marker icon imported from the pinned
  leaflet package as a Vite asset; removes the unpkg.com CDN
  reference (also fixes the leaflet@1.7.1 vs ^1.9.4 mismatch).
- AZ-452 (C05): getApiBase() accessor reading
  VITE_API_BASE_URL. request(), refreshToken(), and createSSE()
  prepend the prefix. Default '' preserves every call site.
- AZ-454 (C07): JSDoc on setToken/getToken documenting the
  test-override intent so future cleanup doesn't delete them.

Also: .env.example documents every VITE_* var; vite-env.d.ts
declares ImportMetaEnv; .gitignore now excludes /dist and
*.tsbuildinfo (tracked-by-mistake cache file removed).

Build verification: `bunx tsc -b --noEmit` passes. No tests in
this run (testability-run exemption per refactor SKILL — tests
land in autodev Step 6).

Co-authored-by: Cursor <cursoragent@cursor.com>

.env.example

@@ -0,0 +1,35 @@
+# Azaion UI — Vite build-time environment variables.
+#
+# All variables here are read at build time via `import.meta.env.VITE_*` and
+# inlined by Vite. Copy this file to `.env.local` (gitignored) for local
+# dev; CI / Docker pass the same variables through the build environment.
+#
+# Every variable is OPTIONAL. When unset, the SPA falls back to production-
+# default behavior:
+#   - VITE_API_BASE_URL  : '' (relative paths; SPA and suite share nginx)
+#   - VITE_OWM_API_KEY   : undefined → getWeatherData returns null
+#   - VITE_OWM_BASE_URL  : https://api.openweathermap.org/data/2.5
+#   - VITE_OSM_TILE_URL  : https://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png
+#   - VITE_ESRI_TILE_URL : https://server.arcgisonline.com/ArcGIS/rest/services/World_Imagery/MapServer/tile/{z}/{y}/{x}
+
+# Prefix for every API request (production: empty; tests / alt deployments: set).
+# A trailing slash is stripped automatically.
+# Example: VITE_API_BASE_URL=http://azaion-ui:80
+VITE_API_BASE_URL=
+
+# OpenWeatherMap API key. Required for the FlightsPage weather feature.
+# Leave unset in CI tests — the e2e profile routes to owm-stub.
+VITE_OWM_API_KEY=<your-openweathermap-api-key>
+
+# OpenWeatherMap REST base URL. Default targets the public endpoint; tests
+# override to point at the owm-stub service.
+# Example for the e2e profile: http://owm-stub:8081/data/2.5
+VITE_OWM_BASE_URL=
+
+# OSM map tile URL template (Leaflet TileLayer.url).
+# Example for the e2e profile: http://tile-stub:8082/{z}/{x}/{y}.png
+VITE_OSM_TILE_URL=
+
+# Esri satellite tile URL template (Leaflet TileLayer.url for the satellite layer).
+# Example for the e2e profile: http://tile-stub:8082/sat/{z}/{y}/{x}
+VITE_ESRI_TILE_URL=