feat(wavelog): push station frequency/mode to Wavelog per operator

Add a CAT integration so the station's current frequency and mode are
reported to each operator's personal Wavelog logbook via Wavelog's radio
API (POST <baseUrl>/index.php/api/radio).

- New plugin rms.wavelog.cat (capability logging.cat.publish): posts
  {key, radio, frequency, mode}. Base URL / radio name come from plugin
  settings or env (WAVELOG_BASE_URL, WAVELOG_RADIO_NAME); no secrets in repo.
- Core hook in the OpenWebRX band-select flow pushes centerFreqHz + startMod
  for the active operator, best-effort (never breaks the band change).
- Per-user Wavelog API key stored on the user record; PUT /v1/me/wavelog-key
  to set it, returned by GET /v1/me and the OpenWebRX session issue response.
- UI: Wavelog API key field in the OpenWebRX panel (visible when generating
  the session link), with i18n (de/en).
- Docs, .env.example entries, and a unit test for the mode mapping.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

docs/plugins/rms-wavelog-cat.md

@@ -0,0 +1,18 @@
+# rms.wavelog.cat
+
+- Zweck: Aktuelle Stationsfrequenz/-mode an ein Wavelog-Logbuch melden (CAT Radio API).
+  Pushed `POST <baseUrl>/index.php/api/radio` mit dem **per-Operator** Wavelog-API-Key, sodass die
+  Frequenz im persoenlichen Wavelog-Konto des aktiven Operators landet (`cat.user_id` = Key-Besitzer).
+- Capabilities: `logging.cat.publish`.
+- Aktionen: `publish` mit Input `{ frequencyHz, mode, apiKey, baseUrl?, radioName? }`.
+- Wichtige Settings/ENV:
+  - `baseUrl` / `WAVELOG_BASE_URL` – URL der Wavelog-Instanz (ohne Slash am Ende). Leer = deaktiviert.
+  - `radioName` / `WAVELOG_RADIO_NAME` – Anzeigename in Wavelog (Default `RMS Remote`).
+  - `timeoutMs` / `WAVELOG_TIMEOUT_MS` – HTTP-Timeout (Default 8000).
+- Ausloeser: Der Core ruft die Capability beim Bandwechsel (`/v1/openwebrx/bands/select`) auf und
+  uebergibt `centerFreqHz` + `startMod` sowie den Wavelog-Key des aktiven Operators. Best-effort:
+  Fehler brechen den Bandwechsel nie ab.
+- Key-Ablage: pro Benutzer in `users.json` (`wavelogApiKey`), setzbar via `PUT /v1/me/wavelog-key`
+  und sichtbar im OpenWebRX-Panel. **Kein** Key im Repo – der Key ist Laufzeit-/Benutzerdatum.
+- Mode-Mapping: `usb|lsb|ssb → SSB`, `cw|cwr → CW`, `fm|nfm|wfm → FM`, `am|sam → AM`, sonst Rohwert
+  in Grossbuchstaben (Wavelog mappt gaengige Rig-Aliase selbst).