fix(maps): make offline tiles cover real trips (cap coherence + zoom-clamp) (#1177)

Closes BLOCKER B5 — the offline map was blank for most real trips:

- The Workbox 'map-tiles' cache held only 1000 entries while the prefetcher
  budgeted ~3413, so prefetched tiles were evicted on arrival. Both caps are
  now a coherent 12288 (~180 MB), kept in sync with cross-referencing comments.
- prefetchTilesForTrip skipped a trip entirely when its all-zooms estimate
  exceeded the cap, so region/road-trip bboxes got no tiles. Removed the
  all-or-nothing guard; prefetchTiles already fills zooms low→high and stops at
  the budget, so large trips now cache the zooms that fit instead of nothing.

client/vite.config.js

@@ -15,21 +15,25 @@ export default defineConfig({
         runtimeCaching: [
           {
             // Carto map tiles (default provider)
+            // maxEntries MUST stay >= MAX_TILES in src/sync/tilePrefetcher.ts
+            // (both are 12288) so prefetched tiles aren't evicted on arrival.
             urlPattern: /^https:\/\/[a-d]\.basemaps\.cartocdn\.com\/.*/i,
             handler: 'CacheFirst',
             options: {
               cacheName: 'map-tiles',
-              expiration: { maxEntries: 1000, maxAgeSeconds: 30 * 24 * 60 * 60 },
+              expiration: { maxEntries: 12288, maxAgeSeconds: 30 * 24 * 60 * 60 },
               cacheableResponse: { statuses: [0, 200] },
             },
           },
           {
             // OpenStreetMap tiles (fallback / alternative)
+            // Shares the 'map-tiles' cache; keep maxEntries equal to the Carto
+            // rule above and MAX_TILES in src/sync/tilePrefetcher.ts (12288).
             urlPattern: /^https:\/\/[a-c]\.tile\.openstreetmap\.org\/.*/i,
             handler: 'CacheFirst',
             options: {
               cacheName: 'map-tiles',
-              expiration: { maxEntries: 1000, maxAgeSeconds: 30 * 24 * 60 * 60 },
+              expiration: { maxEntries: 12288, maxAgeSeconds: 30 * 24 * 60 * 60 },
               cacheableResponse: { statuses: [0, 200] },
             },
           },