Desktop: M3 feature parity with the Android app

- final_transcribe gains optional speaker labeling and library upload:
  diarize_url runs a second tinydiarize pass and merges the turn times
  onto the quality transcript as 'Sprecher 1/2:' labels (diarize_merge,
  port of the Android Diarization object; failures keep the transcript
  unlabeled); library_url uploads the WAV + txt/srt/json bundle with the
  agenda — the server then generates summary + agenda coverage
- WhisperServerEngine supports diarize mode (tinydiarize form field +
  speaker_turn_next parsing); multipart builder handles multiple files
- CLI: --agenda-file, --diarize-url, --library-url (env vars
  MEETREC_DIARIZE_URL / MEETREC_LIBRARY_URL)
- GUI: Library URL + Diarize URL fields and an agenda editor; upload
  progress lands in the status bar
- validated end-to-end against the live servers: recording -> large-v3
  transcription -> txt/srt/json -> library upload (all four files,
  device=desktop) -> server summary/agenda pipeline ran (honest error
  for a noise-only test recording)

README.md

@@ -104,6 +104,9 @@ Key options:
 | `--language`    | force a language code, e.g. `en`, `de` (default: autodetect)     |
 | `--device`      | `auto` / `cpu` / `cuda` (default `auto`); faster-whisper only     |
 | `--compute-type`| `int8` / `int8_float16` / `float16` / `float32` (default `int8`); faster-whisper only |
+| `--agenda-file` | text file with agenda items, one per line — uploaded for the coverage check |
+| `--diarize-url` | tinydiarize server URL → transcript gets `Sprecher 1/2:` labels (or `MEETREC_DIARIZE_URL`) |
+| `--library-url` | meetrec-server URL → uploads the recording and triggers summary + agenda check (or `MEETREC_LIBRARY_URL`) |
 
 `Ctrl+C` stops recording and runs the final transcription.
 
@@ -138,6 +141,22 @@ Notes on `whisper-server`:
 - Run your own with the Docker Compose stack in `server/whisper-server/` — Vulkan GPU (AMD/NVIDIA/Intel), model auto-download, Tailscale-only binding.
 - The server has no authentication: keep it on Tailscale or behind a VPN/firewall.
 - `verbose_json` reports language names ("german") rather than ISO codes.
+
+## Meeting protocol (library, summary, agenda, speakers)
+
+The desktop app has feature parity with the Android app's M3 set:
+
+```sh
+MEETREC_SERVER_URL=http://100.103.83.12:8085 \
+MEETREC_LIBRARY_URL=http://100.103.83.12:8090 \
+MEETREC_DIARIZE_URL=http://100.103.83.12:8086 \
+  meetrec-cli --engine whisper-server --agenda-file agenda.txt -o meeting
+```
+
+- `--library-url` uploads the WAV + transcripts after the final pass; the server then generates the German summary (Ollama, gemma4:12b) and checks which agenda items were discussed (browse everything in the Android app's Library tab).
+- `--agenda-file` supplies the agenda items (one per line).
+- `--diarize-url` adds a second tinydiarize pass whose speaker-turn times are merged onto the transcript as `Sprecher 1:/Sprecher 2:` labels (2 speakers, best-effort on non-English audio; failures keep the transcript unlabeled).
+- The GUI has the same options as fields (Library URL, Diarize URL, agenda editor).
 - `--device` / `--compute-type` do not apply (GPU vs. CPU is decided by the whisper.cpp build).
 
 ## Project layout