feat(cctv): add the City of Toronto RESCU camera pack

The province's 511 pack covers Ontario's highways; this adds the municipal
network underneath it — roughly 336 cameras across downtown arterials plus
the Gardiner, DVP, Allen and Lake Shore, from the City's own open data.

The list is keyless and carries no frame URL, so frame URLs are built from
the convention the dataset documents (`CameraImages/loc####.jpg`) and a
camera number validated as plain digits. The frame proxy is therefore
pinned to the portal origin by construction rather than by trusting a
field. The list fetch refuses redirects, bounds the body it buffers, and
releases the transport on every rejection path.

The dataset publishes no camera facing. `D1`-`D4` look like a compass and
map trivially onto one, but they describe the *comparison* images — static
reference stills captured in 2016 and served from a different path — not
the live pan-tilt-zoom frame. A heading derived from them would be
confidently wrong for every camera in the city, so every camera takes the
shared id-hash fallback at low confidence, as headingless Austin, TfL,
Fintraffic and Calgary cameras do. A test pins that down so it is not
"fixed" later.

Names stay verbatim: the feed's labels are upper-case, and title-casing
would mangle MCCOWAN RD and ST HELEN'S AVE more often than it helped.

Carries the Open Government Licence – Toronto attribution the licence
requires. Disable with `CCTV_TORONTO_ENABLED=0`.

CHANGELOG.md

@@ -1,5 +1,17 @@
 # Changelog
 
+- Add City of Toronto RESCU traffic cameras as a keyless CCTV source pack: the
+  ~336 municipal cameras the Ontario 511 pack does not carry — downtown
+  arterials plus the Gardiner, DVP, Allen and Lake Shore. The list is the
+  City's own open data feed; frames are built from the documented
+  `loc####.jpg` convention and a digits-only camera number, so the frame proxy
+  is pinned to the portal origin by construction. The dataset publishes no
+  camera facing — its `D1`-`D4` fields describe static 2016 comparison images,
+  not the live pan-tilt-zoom frame — so headings use the shared id-hash
+  fallback at low confidence and are corrected with the calibration gizmo.
+  Carries the required Open Government Licence – Toronto attribution. Disable
+  with `CCTV_TORONTO_ENABLED=0`.
+
 - GBFS v3 station names use English translations when available, then the first
   usable translation or short name. Empty or malformed names no longer appear as
   `[object Object]` or interrupt station loading; legacy string names remain