Add MicroslopSam TTS, Flextalk voice profiles, effects, and engine controls

docs/voice.md

@@ -33,7 +33,8 @@ The core reads `VoiceStateStore` only. It never joins a call on its own.
 Rules:
 
 - The channel must be a voice channel. The core validates the snowflake and the channel type.
-- Join joins the call muted. The bot does not capture or send audio.
+- Join joins the call muted and clears self-deafen. Discord persists self-deafen across sessions,
+  and a deafened client receives no call audio, which silences the monitor and the transcript.
 - Voice actions are state changes, not send floods. They stay out of the message pacing queue. The
   daemon spaces them 250-750 ms (`pacedVoice`).
 - The join goes through Discord's internal channel action, located at runtime.
@@ -81,15 +82,108 @@ works as before.
     bytes. `VESKSLOP_TTS_API_KEY` adds a bearer token.
 - `ffplay` decodes and plays into `veskslop_tts` (`PULSE_SINK`). `VESKSLOP_FFPLAY` overrides the
   binary. Lines play one at a time in order.
+- Each line gets a lead-in of silence before the first sample (`VESKSLOP_TTS_LEAD_MS`, default
+  150 ms, maximum 2000). This gives Discord's voice pipeline a moment to settle so the first
+  syllable is not swallowed. The daemon adds it with `adelay` at playback; the engine's file is
+  unchanged. The status reports it as `ttsLeadMs`.
+
+### Per-user volume
+
+Discord stores a playback volume per user (0 to 200, default 100). **0 silences that user**, which
+silences the capture sink even though the stream is uncorked and at 100%: the client mixes the user
+at zero. Read it with `GET /api/voice/volume` (defaults to the current call) or the
+`get_user_volume` MCP tool; the `voice.get` member list and `get_voice_state` carry `volume` too.
+The response also carries the client's own `outputVolume`, which has the same effect when it is 0.
+
+Set it with `POST /api/voice/volume` or `set_user_volume`. The action goes through pacing and is
+written to the action log as `set-volume`.
+
+### Engines
+
+The Speech settings list every configured engine: **espeak-ng**, the command engine
+(`VESKSLOP_TTS_CMD`, shown as `VESKSLOP_TTS_NAME` or "custom engine"), and **HTTP API**
+(`VESKSLOP_TTS_API_URL`). Unavailable engines are disabled. Auto picks the command engine first,
+then espeak-ng, then the API.
+
+Selecting an engine switches the voice list to that engine. The language selector is hidden for
+single-language engines such as the command engine; their voices come from `VESKSLOP_TTS_VOICES`.
+The TTS panel carries the same engine and voice selects plus the speed and pitch sliders.
+
+**Start engine** in the Speech settings warms the selected engine by running one throwaway
+synthesis. For the command engine this starts Xvfb, Wine, and the engine host, so the first real
+line is fast. The result reports the elapsed milliseconds; espeak-ng and the HTTP API need no
+warm-up. The same action is available as `POST /api/audio/tts/warm` and the MCP
+`start_tts_engine` tool.
+
+### Voices
+
+The local engine is espeak-ng. `GET /api/audio/tts/voices` returns every base voice plus the
+espeak variants (`m1`–`m7`, `f1`–`f5`, `croak`, `whisper`) as `<voice>+<variant>`, so each language
+has roughly 15 voices. For natural voices, point `VESKSLOP_TTS_API_URL` at a network TTS (piper,
+OpenAI, ElevenLabs) and pick the `api` provider; `VESKSLOP_TTS_CMD` can also call any local engine
+that accepts `{out}`, `{text_file}`, and `{voice}`.
+
+When `VESKSLOP_TTS_CMD` is set, the daemon hides the espeak list and shows only the voices the
+command declares through `VESKSLOP_TTS_VOICES`. Entries are separated by commas or newlines and
+use `id`, `id|Name`, `id|Name|gender`, `id|Name|gender|language`, or
+`id|Name|gender|language|flags`, where flags are `+`-separated. Flags: `no-pitch` (hide the pitch
+control) and `expression` / `expression=NN` (Flextalk Expression parameter; NN is the registry
+default). The external-engine contract, including speed, pitch, expression, and voice metadata, is
+in [TTS-DESIGN.md](../TTS-DESIGN.md). The bundled engine integration lives in
+[`microslopsam/`](../microslopsam/README.md).
+
+### Speed, pitch, and expression
+
+The TTS panel has a speed slider (0.5x–2.0x, 1.0x is the engine's natural rate) with 0.5x, 0.75x,
+1x, 1.25x, and 1.5x preset buttons, and a pitch slider (-12 to +12 semitones, 0 is natural). Both
+hide for voices whose engine does not support them. Flextalk voices (Keith Bell, Kerry Watson)
+also expose an **Expression** slider (0–100) that changes the voice character; it appears only for
+those voices and defaults to the engine's registry value until moved. Values are stored in the
+daemon preferences and travel to the provider per line; the command provider also receives
+`VESKSLOP_TTS_SPEED`, `VESKSLOP_TTS_PITCH`, and `VESKSLOP_TTS_EXPRESSION`. Absent values mean
+"engine default". `/api/audio/speak` and the MCP `speak` tool accept `speed`, `pitch`, and
+`expression` overrides for a single line.
+
+### Flextalk voice profile (MicroslopSam)
+
+Voices flagged `expression=NN` are Flextalk voices and open the **Flextalk voice profile** window
+from the TTS panel:
+
+- **Voice character** - Pitch, Speaking rate, Prominences, Head size, and Lowering, each showing the
+  voice's engine default and snapping to it within +/-2 units, plus Expression. A value equal to
+  the default clears the override.
+- **Presets** - five named slots stored in `tts.profilePresets`; Save and Load copy the whole
+  profile.
+- **Radio kit** - high-pass (`tts.highpass`, 40-400 Hz, default 40), mono echo (`tts.echo`, 0-100,
+  default 0), and word mode (`tts.words`) with a gap in ms (`tts.wordGapMs`) for the radio/robot
+  character.
+- **Test lines** - Attention, Laboratory, Critical, Health, and Radiation, plus two custom lines
+  kept in `localStorage`. Each button speaks the line with the current profile, so a change can be
+  auditioned without touching the real queue.
+
+The window is movable and recenters every time it opens, so it cannot be lost off screen. Changed
+profile keys travel as `profile` (with `highpass`, `echo`, `words`, and `wordGapMs`) to the command
+provider, which exports `VESKSLOP_TTS_PROFILE`, `VESKSLOP_TTS_HIGHPASS`, `VESKSLOP_TTS_ECHO`,
+`VESKSLOP_TTS_WORDS`, and `VESKSLOP_TTS_WORD_GAP_MS`. The wrapper contract and the registry
+pitfalls (`wine reg import`; never `echo` for the `.reg` key path) are in
+[TTS-DESIGN.md](../TTS-DESIGN.md).
 
 ### Browser monitor (Client audio)
 
 The header **Client audio** button streams the call to the browser:
 
+- The daemon moves the client's playback streams into `veskslop_capture` (match on
+  `application.name` / `application.process.binary`, default `vesktop,electron,chromium,discord`,
+  `VESKSLOP_AUDIO_CLIENT_MATCH` overrides). Without the move the capture sink is silent. The adopt
+  pass runs when devices are set up, when the monitor starts, and every 5 seconds while the monitor
+  or the capture session runs.
 - The daemon reads `veskslop_capture.monitor` with `ffmpeg` and sends raw 48 kHz mono PCM over
   the WebSocket at `/audio`.
 - The browser plays the PCM with the Web Audio API and can send it to a chosen output device.
 - This is separate from the bot's microphone and TTS. Nothing the browser plays affects the call.
+- Diagnose with `cd poc && pnpm audio:doctor`. It prints the default sink, the sink inputs and their
+  sinks, the daemon audio status (`clientMatch`, `adopted`, `lastAdoptError`), and eight seconds of
+  `VOICE_SPEAKING` / `VOICE_STATE_UPDATE` events. Run it during an active call.
 
 Browser microphone puppeting (talking through the bot) is not implemented. It needs a mix sink so
 the browser mic and TTS share `veskslop_mic`, a `pacat` input, and echo handling.
@@ -98,8 +192,9 @@ the browser mic and TTS share `veskslop_mic`, a `pacat` input, and echo handling
 
 When another person speaks, the daemon lowers the `veskslop_tts` sink volume to
 `VESKSLOP_AUDIO_DUCK` percent (default 30) and restores it when they stop. Speaking comes from the
-`VOICE_SPEAKING` event. Staying quiet while someone else talks is a queue property, not a switch.
-Yield (stop mid-line) is not implemented.
+`VOICE_SPEAKING` event. The TTS panel has a **duck on voice** toggle; it is stored in the daemon
+preferences and reported as `duckEnabled` by `/api/audio`. Staying quiet while someone else talks
+is a queue property, not a switch. Yield (stop mid-line) is not implemented.
 
 ### Capture and transcript