refactor(street-level): remove the remaining duplicated code and fakes

A duplicate scan of every module the PR adds (repeated 4-line blocks,
normalised) after gekh's dedup round left these:

- glyphs.js: the cone, ring and position glyphs share cachedGlyph(), wedge(),
  ring() and dot(). Checked with a recording canvas: all 20 draw calls keep
  the same path and fill/stroke state, so the glyphs are pixel-identical.
- panelPositionControls.js: one placeAt() for the three places that pin a
  panel's top-left corner as a fixed window.
- tiles.js: one warn() for the three background-failure logs.
- Tests: src/testSupport/streetLevelFakes.mjs holds the provider snapshot
  (uiState + presentation tests), the stand-in provider (core + controls
  tests) and one real-ray pinhole camera (view + coverage tests, which had
  each written their own). The coverage line-of-sight test still fails when
  refresh() stops passing its focus.
- qa-street-level.mjs: one waitForCoverage() for the five copies of the
  "on, drawn, settled, not key-gated" wait.

No behaviour change: unit 5862 pass, fixture gate 16/16, panel gate 5/5.

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

src/ui/streetLevelPresentation.test.mjs

@@ -5,22 +5,9 @@ import {
   SINCE_STOPS,
   sinceStopIndex,
 } from './streetLevelPresentation.js';
+import { providerSnapshot } from '../testSupport/streetLevelFakes.mjs';
 
-const provider = (overrides = {}) => ({
-  id: 'mapillary',
-  name: 'Mapillary',
-  label: 'MAPILLARY',
-  on: true,
-  configured: true,
-  keyRequired: false,
-  requiresKeyId: 'mapillary',
-  loading: false,
-  count: 0,
-  hint: '',
-  error: null,
-  color: '#05cb63',
-  ...overrides,
-});
+const provider = providerSnapshot;
 
 function snapshot(overrides = {}) {
   const base = {