feat(cctv): add Taiwan Freeway Bureau camera pack

Read ~1,800 national freeway cameras at runtime from the Freeway Bureau's
keyless MOTC 2.0 CCTV.xml table. Each published MJPEG stream maps to the
same camera server's single-JPEG path; only those exact HTTPS pairs on the
four freeway.gov.tw camera servers are registered. On by default,
CCTV_TAIWAN_ENABLED=0 skips it.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

DATA_SOURCES.md

@@ -110,6 +110,7 @@ The optional Local ADS-B layer and the broadcast-FM receiver use radio you recei
   **Quebec is thinly represented**, and that is upstream rather than a filter here: the province runs its own Info-Smog program, so only a handful of Quebec stations appear in ECCC's national feed. The reporting station count also varies hour to hour as stations report or fall silent.
 
 - **Via Lietuva / Eismoinfo (Lithuania).** Public road-camera catalogs and periodically updated still images from [Eismoinfo](https://eismoinfo.lt/), credited to Via Lietuva / eismoinfo.lt in the app. **Off by default.** The camera endpoints are the eismoinfo.lt website backend and are not among the services listed in Via Lietuva's [open-data statement](https://eismoinfo.lt/eismoinfo-backend/content?id=44), whose conditions are attribution and reuse on the same terms. Until the statement is confirmed to cover the camera photos, the pack loads only when an operator sets `CCTV_LITHUANIA_ENABLED=1`; with the flag unset, empty or any other value, the server makes no request to Eismoinfo. `eismoinfo-backend/camera-info-table` is joined by ID to `layer-static-features/VKR`. Without `lks=true`, the latter returns WGS84 `[latitude, longitude]`; the table's `x/y` instead use LKS-94 metres. Only the official HTTPS `/eismoinfo-backend/image-provider/camera/last?id=…` image endpoint is registered. Catalogs use the shared 15-minute cache; frames are fetched on demand and never bundled or archived. These are periodic snapshots, not continuous video. Camera headings are low-confidence estimates. No API key is required. `CCTV_LITHUANIA_MAX_SOURCES` defaults to 400.
+- **Freeway Bureau, MOTC (Taiwan).** National freeway cameras from the Freeway Bureau's keyless [CCTV static table](https://tisvcloud.freeway.gov.tw/history/motc20/CCTV.xml) in the MOTC 2.0 standard, refreshed daily and fetched at runtime (never bundled). Freeway Bureau traffic data is published under the [Open Government Data License, Taiwan (Version 1.0)](https://data.gov.tw/license), which permits reuse with attribution; the app credits the Freeway Bureau, MOTC. The table publishes each camera's MJPEG stream on one of four official camera servers (`cctvn`, `cctvn5`, `cctvc`, `cctvs` under `freeway.gov.tw`). The frame proxy relays single images, so each published stream URL is mapped to the same server's single-JPEG path for the same camera number (`/abs2mjpg/bmjpg` → `/abs2mjpg/jpg`, `/live-view/mjpg/video.cgi` → `/live-view/jpg/image.cgi`); only those exact HTTPS pairs are registered, and the still path is not itself listed in the table. These are on-demand snapshots, not continuous video. Camera headings are low-confidence estimates. No API key is required. On by default; `CCTV_TAIWAN_ENABLED=0` skips the pack, and `CCTV_TAIWAN_MAX_SOURCES` defaults to 600 (bounded to 1–2000).
 
 - **Google Maps Platform.** You supply your own API key and are bound by [Google's ToS](https://cloud.google.com/maps-platform/terms). Google Maps Content (tiles, geocodes, places) **may not be cached, stored, rehosted, or committed** — this app only ever uses it live, which is the compliant pattern. The "Google" attribution is displayed on the globe and must stay visible. Restrict your key (see [SECURITY.md](SECURITY.md)).
 - **OpenSky Network.** Its license is **non-commercial**, and operational use of the REST API in a live product can require a prior written agreement with OpenSky — even for non-profit/government use. If you deploy this commercially, contact OpenSky for your own terms. The flights layer is a toggle and runs anonymously by default.