fix(street-level): address gekh's review of #768

P0
- tileMath: lonToTileX(180) wrapped to column 0, so a whole-world view at
  z1 loaded only the western column; 180 is now the last column.
- coverage.loadTile: a superseded request (after a retire or clear) still
  deleted the newer request's pending entry and loading count in `finally`,
  letting a duplicate load attach lines that nothing could remove. Only the
  request that still owns the key attaches its tile or settles the key.

P1
- view/tileMath: a view across the date line read as a ~358 deg box and
  loaded tiles on the far side of the globe. visibleBbox now returns
  west > east for such views and tilesForBbox splits them at +/-180;
  viewCentre averages across the line.
- decode: the parts of a multi-line sequence were joined into one line,
  drawing straight segments over capture gaps. Each part is now its own
  line (`parts`); later parts carry `~n` in their pick id, and picking or
  recolouring any part acts on the whole sequence.
- viewerHost: a prewarmed MapillaryJS viewer was never destroyed, leaking
  its WebGL context. Prewarmed adapters are tracked and released on
  unmount, at once when the layer went off mid-load, and per provider when
  only that provider is switched off.
- nearestImage took the first record the API returned; it now takes the
  closest one that passes the filter.

P2
- groundCast: the cache was cleared after a request counted its corners,
  dropping ones it relied on; it is now cleared first.
- streetLevelControls: the viewer was resized on every render (every frame
  while a panorama is dragged); the ResizeObserver handles size changes and
  the viewer is resized once when it opens. The legend now rebuilds when its
  entries change, not only their count.
- panelPositionControls: the portable-panel paths this PR added called the
  CCTV viewport sync directly; they go through onPanelResized, which the
  shell routes to CCTV. The "Compose camera panel controls" JSDoc is back on
  _initCctvPanel.

New tests: zoom-1 columns, date-line tiles and bbox, multi-part decode and
part pick ids, nearest image, prewarmed viewer release, and the cache
ordering (fails on the old order).

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

src/ui/panelPositionControls.js

@@ -416,9 +416,6 @@ export class PanelPositionControls {
       // storage unavailable
     }
     this._layoutRightPanels();
-    if (panelId === 'cctv-panel') {
-      this._syncCctvPanelViewport();
-    }
     this._onPanelResized?.(panelId);
   }
 
@@ -629,9 +626,7 @@ export class PanelPositionControls {
           swallowNextClick = false;
         }, 0);
         this._savePanelPosition(panelId, panelEl);
-        if (panelId === 'cctv-panel') {
-          this._syncCctvPanelViewport();
-        }
+        this._onPanelResized?.(panelId);
       };
 
       this._cancelDrag = cancel;
@@ -716,9 +711,6 @@ export class PanelPositionControls {
     const onUp = () => {
       cancel();
       this._savePanelPosition(panelId, panelEl);
-      if (panelId === 'cctv-panel') {
-        this._syncCctvPanelViewport();
-      }
       this._onPanelResized?.(panelId);
     };