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`.

server/providers/cctv/sources.js

@@ -55,6 +55,12 @@ import {
   DEFAULT_CALGARY_MAX_SOURCES,
   CALGARY_DOWNTOWN,
   CALGARY_MAX_CATALOG_BYTES,
+  TORONTO_RESCU_LIST_URL,
+  TORONTO_RESCU_IMAGE_ORIGIN,
+  DEFAULT_TORONTO_MAX_SOURCES,
+  TORONTO_DOWNTOWN,
+  TORONTO_GROUND_ELEVATION_M,
+  TORONTO_MAX_CATALOG_BYTES,
   CCTV_SOURCE_FETCH_TIMEOUT_MS,
   DELDOT_CCTV_URL,
   DEFAULT_DELDOT_MAX_SOURCES,
@@ -83,12 +89,16 @@ import {
   isLikelyNswCoordinate,
   isLikelyCalgaryCoordinate,
   isLikelyNorwayCoordinate,
+  isLikelyTorontoCoordinate,
   cameraDisplayCode,
   rowArrayToObject,
   prioritizeSources,
 } from './normalize.js';
 import { directionToHeading } from '../../../src/data/directionText.js';
-import { readResponseJsonCapped } from '../common/http.js';
+import {
+  readResponseJsonCapped,
+  readResponseTextCapped,
+} from '../common/http.js';
 /**
  * Fetch and parse Austin traffic camera records from the city Open Data portal.
  *
@@ -1863,3 +1873,172 @@ export async function loadVegvesenSourcesFromOpenData() {
     return [];
   }
 }
+
+/**
+ * The JSONP envelope the City of Toronto wraps its camera list in. Anchored at
+ * both ends, so only that exact callback is unwrapped — a payload that merely
+ * contains the name somewhere is not treated as the list.
+ */
+const RESCU_JSONP = /^jsonTMCEarthCamerasCallback\(([\s\S]*)\)\s*;?$/;
+
+/**
+ * Unwrap the RESCU camera list. The portal serves the list as JSONP; should it
+ * ever drop the wrapper, the bare JSON document still parses. Anything else —
+ * a foreign callback, a truncated body, an error page — yields no cameras
+ * rather than a thrown loader.
+ *
+ * @param {string} text - Raw response body.
+ * @returns {Array<object>} The `Data` rows, or [] when the body is unusable.
+ */
+export function parseRescuCameraList(text) {
+  const body = String(text ?? '').trim();
+  if (!body) return [];
+  const unwrapped = RESCU_JSONP.exec(body)?.[1] ?? body;
+  try {
+    const parsed = JSON.parse(unwrapped);
+    const rows = parsed?.Data ?? parsed?.data;
+    return Array.isArray(rows) ? rows : [];
+  } catch {
+    return [];
+  }
+}
+
+/**
+ * Convert one RESCU list row into a camera source.
+ *
+ * The row carries no URL: the frame URL is built from the documented
+ * `loc####.jpg` convention and a camera number validated as plain digits, so
+ * the frame proxy is pinned to the city origin by construction and no upstream
+ * field — present or planted — can steer it.
+ *
+ * No compass heading exists in this dataset. `D1`-`D4` are the directions of
+ * the *comparison* images (static reference stills captured in 2016, served
+ * from a different path); the live frame is one pan-tilt-zoom camera pointing
+ * wherever the operator left it. Treating those letters as a facing would put
+ * a confident, wrong bearing on every camera in the city, so every row takes
+ * the id-hash fallback and the low-confidence pose, as headingless Austin,
+ * TfL, Fintraffic and Calgary cameras do.
+ *
+ * @param {object} row - One entry from the RESCU `Data` array.
+ * @returns {object|null} Normalized camera source, or null when unusable.
+ */
+export function torontoCameraToSource(row) {
+  if (!row || typeof row !== 'object') return null;
+  const number = String(row.Number ?? row.number ?? '').trim();
+  // Plain digits only: a number is about to become a URL path segment.
+  if (!/^\d{1,6}$/.test(number)) return null;
+
+  const lat = toFiniteNumber(row.Latitude ?? row.latitude);
+  const lon = toFiniteNumber(row.Longitude ?? row.longitude);
+  if (!isLikelyTorontoCoordinate(lat, lon)) return null;
+
+  const cameraId = `toronto-${number}`;
+  // The feed's own label, verbatim. It is upper-case ("MCCOWAN RD", "ST
+  // HELEN'S AVE"); title-casing it would mangle more names than it fixed.
+  const name =
+    String(row.Name ?? row.name ?? '')
+      .replace(/\s+/g, ' ')
+      .trim() || `Toronto Camera ${number}`;
+
+  return {
+    id: cameraId,
+    name,
+    city: 'Toronto',
+    cityId: 'toronto',
+    provider: 'City of Toronto',
+    lat,
+    lon,
+    headingDeg: fallbackHeadingFromId(cameraId),
+    headingConfidence: 'low',
+    pitchDeg: -18,
+    fovDeg: 44,
+    rangeM: 145,
+    mountHeightM: 8,
+    groundElevationM: TORONTO_GROUND_ELEVATION_M,
+    feedType: 'image',
+    url: `${TORONTO_RESCU_IMAGE_ORIGIN}loc${number}.jpg`,
+    snapshotUrl: `${TORONTO_RESCU_IMAGE_ORIGIN}loc${number}.jpg`,
+    sourceKind: 'toronto-rescu-open-data',
+    license:
+      'Contains information licensed under the Open Government Licence – Toronto',
+    // Unselected-label code: the intersection, so a camera at rest reads as a
+    // place rather than as its id.
+    code: cameraDisplayCode(name.toUpperCase()),
+  };
+}
+
+/**
+ * Fetch City of Toronto RESCU traffic cameras from the City's open data
+ * portal, keyless. One JSONP list for the whole city; frames are stills on the
+ * same portal origin.
+ *
+ * The list fetch refuses redirects (`redirect: 'manual'`) so the list host
+ * cannot be steered, and caps the body it will buffer.
+ *
+ * Attribution: Open Government Licence – Toronto, registered in
+ * src/data/dataCredits.js.
+ *
+ * @returns {Promise<Array<object>>} Normalized camera source objects.
+ */
+export async function loadTorontoSourcesFromOpenData() {
+  try {
+    const endpoint =
+      process.env.CCTV_TORONTO_LIST_URL || TORONTO_RESCU_LIST_URL;
+    const resp = await fetch(endpoint, {
+      headers: { Accept: 'application/json, text/javascript' },
+      redirect: 'manual',
+      signal: AbortSignal.timeout(CCTV_SOURCE_FETCH_TIMEOUT_MS),
+    });
+    // A response this loader will not read still owns its transport until the
+    // body is released, so every rejection path cancels before returning.
+    const discard = async () => {
+      try {
+        await resp.body?.cancel();
+      } catch {
+        /* no-op */
+      }
+      return [];
+    };
+    if (resp.status >= 300 && resp.status < 400) {
+      console.warn(
+        '[CCTV] Toronto camera list redirected; redirects are not followed',
+      );
+      return discard();
+    }
+    if (!resp.ok) {
+      console.warn('[CCTV] Toronto camera download failed:', resp.status);
+      return discard();
+    }
+    const text = await readResponseTextCapped(resp, TORONTO_MAX_CATALOG_BYTES);
+    const rows = parseRescuCameraList(text);
+    if (!rows.length) return [];
+
+    const cameras = [];
+    const seen = new Set();
+    for (const record of rows) {
+      const camera = torontoCameraToSource(record);
+      if (!camera || seen.has(camera.id)) continue;
+      seen.add(camera.id);
+      cameras.push(camera);
+    }
+    const maxRaw = Number(
+      process.env.CCTV_TORONTO_MAX_SOURCES || DEFAULT_TORONTO_MAX_SOURCES,
+    );
+    const maxCount = Number.isFinite(maxRaw)
+      ? Math.max(8, Math.min(500, Math.floor(maxRaw)))
+      : DEFAULT_TORONTO_MAX_SOURCES;
+    const prioritized = prioritizeSources(cameras, maxCount, [
+      TORONTO_DOWNTOWN,
+    ]);
+    console.log(
+      `[CCTV] Loaded Toronto camera sources: ${cameras.length} (using nearest ${prioritized.length})`,
+    );
+    return prioritized;
+  } catch (error) {
+    console.warn(
+      '[CCTV] Toronto camera download error:',
+      error?.message || error,
+    );
+    return [];
+  }
+}