feat(cctv): King County road camera source pack (Washington State)

Adds King County DOT Road Services' cameras as a keyless source pack, from
the county's public ArcGIS FeatureServer layer ("King County and WSDOT
Traffic Cameras"). 59 live cameras against the current feed.

- The `outFields` list is explicit on purpose: the layer also carries
  asset-administration columns (including staff names) that must never be
  fetched.
- Only live, active cameras with frames on the county's own
  info.kingcounty.gov image handler are registered; the feed writes http://
  and the handler serves HTTPS, so URLs are upgraded and pinned before
  registration. WSDOT-owned rows are skipped so a camera never appears twice
  when a statewide WSDOT pack is present; the few city-owned cameras the
  county hosts (Redmond, Sammamish, Newcastle, Snoqualmie) carry their owner
  as the per-camera credit, DriveBC-style.
- The layer publishes no facing: headings use the shared id-hash fallback at
  low confidence, correctable with the calibration gizmo.
- Uniquely among the packs, the county publishes each camera's hardware
  Manufacturer/Model (Cohu 3950/3965, Bosch AUTODOME IP 5000i, Axis
  Q6135-LE, Siqura PD910). The model string is whitespace-collapsed (the
  feed carries stray newlines) and carried on the source as `model`, with an
  additive passthrough in normalizeSourceItem (same pattern as poseSource)
  so identified-hardware consumers can use it. All 59 live cameras carry a
  model value.
- Attribution per the KCGIS Center terms, registered in the attribution
  popover and documented in DATA_SOURCES.md.
- Defaults: the whole catalog loads (125 cap); CCTV_KINGCOUNTY_MAX_SOURCES
  changes the cap, CCTV_KINGCOUNTY_ENABLED=0 turns the pack off.
- Tests: filtering (owner/live/status/host/geometry/bbox), HTTPS upgrade,
  model whitespace-collapse and passthrough, partner-city credit, env cap,
  upstream-failure fallback, and normalizeSourceItem model semantics.

server/providers/cctv/catalog.js

@@ -18,6 +18,7 @@ import {
   loadNswSourcesFromOpenData,
   loadCalgarySourcesFromOpenData,
   loadDelDOTSourcesFromOpenData,
+  loadKingCountySourcesFromOpenData,
 } from './sources.js';
 
 /** Env kill switch: unset or anything but "0" means enabled. */
@@ -92,6 +93,11 @@ const LIVE_PACKS = [
     enabled: () => envEnabled('CCTV_DELDOT_ENABLED'),
     load: loadDelDOTSourcesFromOpenData,
   },
+  {
+    name: 'kingcounty',
+    enabled: () => envEnabled('CCTV_KINGCOUNTY_ENABLED'),
+    load: loadKingCountySourcesFromOpenData,
+  },
 ];
 /**
  * Load CCTV sources from a local JSON file (CCTV_SOURCES_FILE env or default).