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/normalize.js

@@ -516,5 +516,13 @@ export function normalizeSourceItem(item) {
     // badge can distinguish them from raw automated priors (e.g. Austin Open
     // Data, which never sets this field). Passed through as-is to the client.
     poseSource: item.poseSource === 'curated' ? 'curated' : undefined,
+    // Optional hardware-model passthrough (additive, like poseSource): packs
+    // whose catalog publishes the camera's hardware model — King County's
+    // layer carries Manufacturer/Model per camera — pass it through so
+    // identified-hardware consumers can use it. Absent everywhere else.
+    model:
+      typeof item.model === 'string' && item.model.trim()
+        ? item.model.trim()
+        : undefined,
   };
 }