fix(street-level): camera ownership, mesh refresh, panel CSP (Sameh's review)

- Photo framing and FOLLOW claim the camera through the application's
  navigation, injected with attachNavigation({ run, subscribeHandoff }):
  aircraft and satellite tracking is released first, the cockpit refuses,
  and FOLLOW stops when another feature takes the camera. No UI imports
  in the layer.
- The mesh sampler follows the mesh floor's rules: it waits for the
  visible tileset to finish streaming (visibleTilesetLoaded, now exposed
  by the mesh floor service), needs a real bare-earth prior and keeps to
  the shared meshFloorSampleWithinPrior window, which cameraFollow now
  uses too. A cell is probed again once the camera is half as far from
  it (down to 40 m), so a coarse early sample is replaced and redrawn.
- The MCP globe panel's CSP allows the Mapillary Graph API and its image
  CDN (https://*.xx.fbcdn.net).
- The tile proxy reads bodies with the shared readResponseBytesCapped.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

docs/CURRENT-STATE.md

@@ -2959,7 +2959,10 @@ the mesh hides what is behind buildings and trees. A tile is drawn draped until
 its heights arrive; a geoid fallback leaves it draped. Within 900 m of the
 camera, `meshSampler.js` samples the rendered surface (`scene.sampleHeight`,
 ~11 m cells, nearest first, 6 ms idle budget) so lines also follow trenches,
-steep streets and roads under trees. Roads on elevated decks are still drawn at
+steep streets and roads under trees. It uses the mesh floor's rules (the
+visible tileset has finished streaming, a real bare-earth prior, the shared
+mesh window) and probes a cell again once the camera is half as far from it,
+down to 40 m, so coarse early samples are replaced as finer tiles load. Roads on elevated decks are still drawn at
 ground level. Framing a photo ignores mesh samples far below the bare earth
 (unloaded tiles).
 
@@ -2967,7 +2970,10 @@ The header pill is the layer switch. With one provider its chip is a layer
 switch too; with several, darkening the last lit chip turns the layer off. The
 viewer sits under the header with EXPAND, FIT/FILL, FOLLOW and close above the
 image. FOLLOW needs the Google 3D map stack (`attachMapStackController`) and
-stops when the stack changes. SINCE is a stepped slider whose readout names the
+stops when the stack changes. Framing a photo and turning FOLLOW on claim the
+camera through the application's navigation (`attachNavigation`), which
+releases aircraft and satellite tracking (and is refused in the cockpit);
+FOLLOW stops when another feature takes the camera. SINCE is a stepped slider whose readout names the
 cut-off date. The panel is portable (`street-level-panel` spec, minimum
 320 × 280, `dockOnCollapse`): a floating window gives spare height to the
 viewer, and collapsing it, double-clicking the header or SHRINK after EXPAND