fix(cctv): make the Lithuania pack opt-in until its licence is confirmed

The camera endpoints are the eismoinfo.lt website backend, which the Via
Lietuva open-data statement does not list, so the pack now follows the NYC
opt-in pattern (CCTV_LITHUANIA_ENABLED=1) and the docs say why. A failed
catalog request now aborts its sibling instead of leaving it open until the
timeout, and a redirect is logged as not followed.

DATA_SOURCES.md

@@ -91,7 +91,7 @@ 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. The provider's [open-data statement](https://eismoinfo.lt/eismoinfo-backend/content?id=44) describes reuse of its public data; no specific Creative Commons licence is asserted here. `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. Disable with `CCTV_LITHUANIA_ENABLED=0`; `CCTV_LITHUANIA_MAX_SOURCES` defaults to 400.
+- **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.
 
 - **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.