Add geotag "Places" map with raster LOD tile pyramid

New src/map.c (unity-build part) adds a map screen reached from the search
bar's map button:
- Fetches geotag markers (GET /api/map/markers), projects with Web Mercator.
- Clusters markers into count "bubbles" in map space (anchored to the world,
  so panning translates them instead of reshuffling); pan (d-pad/touch),
  zoom (L/R/pinch). X or tap zooms into a cluster, or opens a lone/co-located
  photo — fetching that asset on demand if it isn't paged into the grid —
  and returns to the map on back.
- Base map: a Web-Mercator LOD tile pyramid generated offline from a MapChart
  PNG (tools/png_to_tiles.py -> assets/maptiles.pak); the level matching the
  on-screen scale is drawn from 256px JPEG tiles decoded into pooled textures
  (the crash-safe path), with a coarse overview underneath so there are no
  gaps while tiles stream in. Georeferencing (full longitude, lat band) was
  fit from isolated-island centroids so markers land on land.

main.c uses a larger vita2d vertex pool; app.c wires the mode in.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/main.c

@@ -154,6 +154,7 @@ static char (*g_tex_err)[160];
 #include "thumbs.c"    /* background thumbnail loader + texture pool     */
 #include "display.c"   /* merged server+local timeline + grid layout     */
 #include "ui.c"        /* grid/detail/search/login/cloud screens         */
+#include "map.c"       /* geotag map: markers, clustering, projection    */
 #include "video.c"     /* video download + SceAvPlayer playback          */
 #include "sync.c"      /* local scan/hash/check/upload + sync overview   */
 #include "app.c"       /* main(): init, event loop, threads             */