Merge upstream/main into pr/panoramax

CHANGELOG: keep both new [Unreleased] entries (Panoramax, and the
emergency-transponder highlight from #856).

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

DATA_SOURCES.md

@@ -27,7 +27,7 @@ How to read this:
 | **OpenStreetMap** | Map and place data (roads, military areas and names, ALPR, place search, outlines); via vector tiles, hourly ALPR extract, bundled data, Nominatim and optional self-configured Overpass | [ODbL 1.0](https://opendatacommons.org/licenses/odbl/1-0/) | © OpenStreetMap contributors |
 | **Google Map Tiles API** (Photorealistic 3D Tiles) + Places/Geocoding | The 3D globe, voice scene context, and on-demand nearby installation search                                                         | Google Maps Platform ToS (proprietary, your own key + billing)                                                                                                                                                                                                                                                                                        | "Google" / "Google Maps" logo — **shown in-app**, required                                                                                  |
 | **OpenSky Network**                                                   | Primary worldwide live-flight snapshot                                                                                              | Non-commercial research/education license                                                                                                                                                                                                                                                                                                             | Schäfer et al., _"Bringing Up OpenSky"_, IPSN 2014 + opensky-network.org                                                                    |
-| **adsb.lol point API**                                                | Bounded live-flight fallback when OpenSky has no usable snapshot                                                                    | ODbL 1.0                                                                                                                                                                                                                                                                                                                                              | adsb.lol contributors; `api.adsb.lol/v2/lat/{lat}/lon/{lon}/dist/{radius}`                                                                  |
+| **adsb.lol point API**                                                | Bounded live-flight fallback when OpenSky has no usable snapshot; GNSS Integrity layer (aircraft-reported NIC/NACp and GPS-loss integrity facts, via `/api/gnss-integrity`, 60 s server cache)                                                                    | ODbL 1.0                                                                                                                                                                                                                                                                                                                                              | adsb.lol contributors; `api.adsb.lol/v2/lat/{lat}/lon/{lon}/dist/{radius}`                                                                  |
 | **adsb.lol**                                                          | Military flights + aircraft traces                                                                                                  | ODbL 1.0                                                                                                                                                                                                                                                                                                                                              | "adsb.lol" (ODbL)                                                                                                                           |
 | **adsbdb** (`api.adsbdb.com`) | Aircraft type, model name and registration by ICAO hex for enriched flights; airline and origin/destination airports for the tracked flight's callsign | No licence or rate limit is published for the service. Its own credits: aircraft data from PlaneBase, ICAO-to-N-number conversion by Guillaume Michel, and flight route data that "is the work of David Taylor, Edinburgh and Jim Mason, Glasgow, and may not be copied, published, or incorporated into other databases without the explicit permission of David J Taylor, Edinburgh" | "adsbdb — api.adsbdb.com" (courtesy); route data credited to David Taylor, Edinburgh, and Jim Mason, Glasgow |
 | **AISStream.io**                                                      | Live vessels (AIS)                                                                                                                  | Free, beta, no formal ToS; AIS is a public broadcast                                                                                                                                                                                                                                                                                                  | "AISStream.io" (courtesy)                                                                                                                   |
@@ -81,6 +81,41 @@ The optional Local ADS-B layer and the broadcast-FM receiver use radio you recei
 - **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.
 - **adsb.lol flight fallback.** When OpenSky is unavailable and no last-good OpenSky response exists, the server requests a cached, capped 250 nm adsb.lol point snapshot around the current camera subpoint. This is regional observed context, not worldwide completeness; provenance is exposed in the Flights stats/context row. Military ICAOs remain reconciled through the existing dedicated military registry rather than duplicated.
+<a id="gnss-integrity"></a>
+
+- **GNSS integrity (adsb.lol).** A separate keyless point request samples a 250 nm
+  circle around the screen centre, snapped once to whole degrees. This does not
+  reuse the Flights fallback cache. Cache lifetime is 60 s; 429 backoff is capped
+  at one hour and other upstream failures cool down for 15 s. Future access may
+  require feeder keys under the [API terms](https://github.com/adsblol/api).
+  Airborne decoded ADS-B v1/v2 aircraft with a known 0–60 s position age qualify,
+  including MLAT-positioned aircraft still broadcasting their own quality.
+  TIS-B/MLAT-derived NIC and NACp are ignored. GPS-loss evidence uses
+  `gpsOkLat/gpsOkLon` when present, otherwise the current known position.
+  The proxy strips identity metadata and tags its response with classifier
+  `gev-nic-nacp-v2`; rows carry only integrity facts.
+
+  The method has three separately attributed parts:
+  1. **GEV classifier (unvalidated):** GPS-loss flag, aircraft-reported NACp < 8,
+     or aircraft-reported NIC < 7 except NIC 0 with NACp ≥ 10 (unknown containment).
+     The numerical minima come from US 14 CFR 91.227(c), not a published jamming
+     classifier. Readsb's [JSON contract](https://github.com/wiedehopf/readsb/blob/dev/README-json.md)
+     describes the quality field origins and GPS-loss flag.
+  2. **GPSJAM aggregation:** score = `100 × max(0, bad − 1) / total`, with percent
+     bands < 2, 2–10, > 10. One bad aircraft is discounted. This is not the raw
+     share of bad aircraft. See the [GPSJAM FAQ](https://gpsjam.org/faq).
+  3. **GEV window:** 30 minutes over visited views, at least three aircraft per
+     0.5° cell. These bands were developed for daily totals; with fewer than ten
+     observations a cell can skip the middle band. Source timestamps date evidence
+     even through cache replays, and degraded evidence expires independently.
+
+  Medium/high cells report navigation-integrity anomalies. Interference is one
+  possible explanation, not a detected or located emitter. Avionics faults and
+  manoeuvring military trainers can also lower reported accuracy. Blank areas
+  can be outside coverage or lack enough observations. Attribution: adsb.lol
+  contributors, ODbL 1.0; GPSJAM for aggregation only.
+
+
 - **adsbdb enrichment.** `/api/adsbdb` resolves an ICAO hex to aircraft type, model name and registration, and the tracked flight's callsign to an airline and an origin/destination pair. Fan-out is deliberately small because adsbdb is a free community API that publishes no quota: at most 4 requests in flight, dispatches dripped to roughly 5/s, and each key asked for at most once per session, with route lookups reserved for the tracked aircraft. The dev-server proxy caches each key for 24 hours in `.gev-cache/adsbdb.json`, negative answers included, so fresh entries survive server restarts. That gitignored cache remains local to the deployment and is not bundled with this repo. adsbdb publishes no general service license; its README says the route data may not be copied, published, or incorporated into other databases without the explicit permission of David J Taylor, Edinburgh. Deployers are responsible for obtaining any permission their use requires. Enrichment is best-effort and fail-silent — a flight that gets no answer keeps what the flight feed already gave it.
 - **Launch Library 2.** `/api/launches` makes a server-side rolling-30-day query against the supported v2.3 detailed launch endpoint, caches successful responses for 15 minutes in memory and on disk, and serves the last successful response during a throttle or transient outage. Anonymous access is limited to 15 calls/hour; deployments can provide `LL2_API_TOKEN` for authenticated access. The Space Devs' published terms permit using and sharing the API data in any form, ask users not to forward it without adding value, disclaim complete accuracy, and encourage—but do not require—attribution. This app keeps a courtesy credit. Payload and stage/recovery records are shown only when supplied. Failed launches expose their source status and never receive fallback orbit geometry or a live/estimated marker. LL2 supplies launch context and event timing, not continuous ascent telemetry or live orbital state.
 - **TfL JamCams.** The camera list comes from the keyless `api.tfl.gov.uk` endpoint (an optional `TFL_APP_KEY` raises its rate limit); frames come from TfL's public S3 bucket. The "Powered by TfL Open Data" attribution is required by TfL's terms and is registered in the Data attribution popover.