refactor(street-level): rename the Mapillary layer to street-level

Pure move: the layer id, panel id, CSS prefix, classes, exports and config
paths become provider-neutral (street-level, #street-level-panel, sl-);
the Mapillary-specific modules move under providers/mapillary/. Behaviour
is unchanged. The two sprite collections now register under distinct ids
instead of overwriting each other under 'mapillary'.

Co-Authored-By: Claude Fable 5.1 <[email protected]>

src/layers/streetLevel/providers/mapillary/policy.js

@@ -0,0 +1,54 @@
+/** Identity and tuning for the Mapillary street-level layer. */
+export const STREET_LEVEL_LAYER_ID = 'street-level';
+export const MAPILLARY_KEY_ID = 'mapillary';
+export const MAPILLARY_GRAPH_HOST = 'https://graph.mapillary.com';
+
+/** Stable id prefixes for picked primitives. */
+export const PICK_PREFIX = Object.freeze({
+  sequence: 'mly:seq:',
+  image: 'mly:img:',
+  position: 'mly:pos',
+});
+
+/** Brand green for coverage; panoramas get a distinct hue; selection is GEV cyan. */
+export const COLORS = Object.freeze({
+  coverage: '#05cb63',
+  coverageOld: '#2e7d5b',
+  pano: '#ff4fd8',
+  selected: '#00d4ff',
+  image: '#e8eaed',
+  position: '#ffb300',
+});
+
+/** Camera-driven coverage refresh. */
+export const COVERAGE_MOVE_DEBOUNCE_MS = 320;
+export const COVERAGE_MAX_TILES = 9;
+/** Overview (z0–5) coverage points seen from orbit. */
+export const COVERAGE_OVERVIEW_MAX_TILES = 16;
+export const COVERAGE_OVERVIEW_POINT_PX = 2.5;
+export const COVERAGE_MAX_SEQUENCES = 6000;
+export const COVERAGE_LINE_WIDTH_PX = 2.5;
+/** Sequences newer than this many days draw at full brightness. */
+export const COVERAGE_RECENT_DAYS = 730;
+
+/** Per-sequence image cones after a sequence is selected. */
+export const SEQUENCE_IMAGES_LIMIT = 2000;
+export const IMAGE_CONE_SIZE_PX = 26;
+export const IMAGE_CONE_MIN_SPACING_M = 3;
+
+/** Nearest-image search when the user asks to look at a place. */
+export const NEAREST_RADIUS_M = 50;
+export const NEAREST_LIMIT = 8;
+
+/**
+ * On-globe credit shown while the layer is enabled. Mapillary imagery and
+ * derived data are CC BY-SA 4.0 and require visible attribution.
+ */
+export const MAPILLARY_CREDIT_HTML =
+  'Street Level: imagery © <a href="https://www.mapillary.com" target="_blank" rel="noopener">Mapillary</a> contributors, CC BY-SA 4.0';
+
+/** Fields requested from the graph API. */
+export const IMAGE_FIELDS =
+  'id,captured_at,compass_angle,computed_compass_angle,geometry,computed_geometry,computed_altitude,is_pano,sequence,thumb_256_url,creator,quality_score';
+export const SEQUENCE_IMAGE_FIELDS =
+  'id,captured_at,compass_angle,geometry,is_pano,computed_altitude';