refactor(street-level): one provider, no orbit overview, no prewarm, simpler tile choice

The layer now owns its Mapillary parts directly: the provider registry,
pick router, multi-provider UI summary, params codec helper and provider
context are gone. createStreetLevelLayer({ source }) builds coverage,
sequences, the nearest-image lookup and the MapillaryJS viewer itself; a
single providerOn switch keeps the share link's `mapillary` option (off
draws nothing), and getParams/setParams keep { mapillary, pano, sinceDays }.

No z0-5 overview points: above 60 km nothing is drawn and the panel says to
zoom in; the proxy now serves only coverage z11-14. Tiles come from the
visible ground within range of the camera, ranked from the ground under it
(no line-of-sight ranking or near-range padding). MapillaryJS loads on the
first photo; viewer prewarm is removed. Key status, a rejected key and a
rate limit share one `blocked` state on coverage.

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

src/layers/streetLevel/uiState.test.mjs

@@ -1,139 +0,0 @@
-import assert from 'node:assert/strict';
-import test from 'node:test';
-import { composeUIState, summarizeCoverage } from './uiState.js';
-import { COLORS } from './policy.js';
-import { providerSnapshot } from '../../testSupport/streetLevelFakes.mjs';
-
-const provider = (overrides = {}) =>
-  providerSnapshot({ count: 10, ...overrides });
-const base = {
-  enabled: true,
-  filter: { pano: 'all', sinceDays: 0 },
-  street: { open: false },
-  sequence: { selectedId: null, images: 0, loading: false },
-};
-
-test('counts add up across active providers only', () => {
-  const ui = composeUIState({
-    ...base,
-    providers: [
-      provider(),
-      provider({ id: 'panoramax', name: 'Panoramax', count: 5, on: false }),
-      provider({ id: 'kartaview', name: 'KartaView', count: 7, loading: true }),
-    ],
-  });
-  assert.equal(ui.coverage.count, 17);
-  assert.equal(ui.coverage.loading, true);
-});
-
-test('the layer is key-gated only when every switched-on provider lacks its key', () => {
-  const gated = composeUIState({
-    ...base,
-    providers: [provider({ keyRequired: true })],
-  });
-  assert.equal(gated.keyRequired, true);
-  const mixed = composeUIState({
-    ...base,
-    providers: [
-      provider({ keyRequired: true }),
-      provider({ id: 'panoramax', name: 'Panoramax', requiresKeyId: null }),
-    ],
-  });
-  assert.equal(mixed.keyRequired, false, 'a keyless provider still draws');
-  const offOnly = composeUIState({
-    ...base,
-    providers: [provider({ keyRequired: true, on: false })],
-  });
-  assert.equal(offOnly.keyRequired, false, 'nothing switched on to gate');
-});
-
-test('the legend is one swatch per active source, in its colour, then Selected', () => {
-  const single = composeUIState({ ...base, providers: [provider()] });
-  assert.deepEqual(single.legend, [
-    { key: 'mapillary', label: 'Mapillary', color: '#05cb63' },
-    { key: 'selected', label: 'Selected', color: COLORS.selected },
-  ]);
-  const two = composeUIState({
-    ...base,
-    providers: [
-      provider(),
-      provider({ id: 'panoramax', name: 'Panoramax', color: '#a66bff' }),
-    ],
-  });
-  assert.deepEqual(
-    two.legend.map((entry) => [entry.label, entry.color]),
-    [
-      ['Mapillary', '#05cb63'],
-      ['Panoramax', '#a66bff'],
-      ['Selected', COLORS.selected],
-    ],
-  );
-  const oneOff = composeUIState({
-    ...base,
-    providers: [
-      provider(),
-      provider({ id: 'panoramax', name: 'Panoramax', on: false }),
-    ],
-  });
-  assert.deepEqual(
-    oneOff.legend.map((entry) => entry.key),
-    ['mapillary', 'selected'],
-  );
-  assert.deepEqual(
-    composeUIState({ ...base, providers: [provider({ on: false })] }).legend,
-    [],
-  );
-});
-
-test('hint and error come from the first active provider that has one', () => {
-  const ui = composeUIState({
-    ...base,
-    providers: [
-      provider({ hint: '', error: null }),
-      provider({ id: 'b', name: 'B', hint: 'Look down', error: 'boom' }),
-    ],
-  });
-  assert.equal(ui.coverage.hint, 'Look down');
-  assert.equal(ui.coverage.error, 'boom');
-  assert.deepEqual(ui.filter, base.filter);
-  assert.notEqual(ui.filter, base.filter, 'snapshot copies the filter');
-});
-
-test('summarizeCoverage is what getStats reports, without building a snapshot', () => {
-  assert.deepEqual(
-    summarizeCoverage([
-      provider({ count: 4, hint: 'Look down' }),
-      provider({ id: 'b', name: 'B', count: 6, loading: true, error: 'boom' }),
-      provider({ id: 'c', name: 'C', count: 99, on: false, keyRequired: true }),
-    ]),
-    {
-      count: 10,
-      loading: true,
-      hint: 'Look down',
-      error: 'boom',
-      keyRequired: false,
-      keyRejected: false,
-    },
-  );
-  assert.equal(summarizeCoverage([]).keyRequired, false);
-});
-
-test('a rejected key gates like a missing one and is named as rejected', () => {
-  const rejected = provider({
-    keyRequired: true,
-    keyRejected: true,
-    error: 'Mapillary rejected MAPILLARY_CLIENT_TOKEN',
-  });
-  const summary = summarizeCoverage([rejected]);
-  assert.equal(summary.keyRequired, true);
-  assert.equal(summary.keyRejected, true);
-  assert.equal(summary.error, 'Mapillary rejected MAPILLARY_CLIENT_TOKEN');
-  const state = composeUIState({ ...base, providers: [rejected] });
-  assert.equal(state.keyRequired, true);
-  assert.equal(state.keyRejected, true);
-  // A provider that is merely missing its key is not "rejected".
-  assert.equal(
-    summarizeCoverage([provider({ keyRequired: true })]).keyRejected,
-    false,
-  );
-});