Fix Flextalk buzz: REG_DWORD speaker settings; measured pitch/speed mapping; fixed-gain normalization

docs/TTS-DESIGN.md

@@ -267,7 +267,8 @@ record what the engine needs to interpret, add, or hide._
 
 ### Quirks the wrapper must hide
 
-- Flextalk reports default pitch/speed as maximum through `ITTSAttributes`.
+- Flextalk numeric speaker settings must be `REG_DWORD`; `REG_SZ` values make the engine
+  synthesize a buzz. `setup/setup-flextalk.sh` writes them correctly.
 - The mode list includes TruVoice names with no installed voice data; filter those out of
   `/voices` (or mark them `unavailable`).
 - Wine needs a working X display; the project helper starts a persistent Xvfb.
@@ -301,6 +302,19 @@ _Added 2026-09-15._
 - **Display**: the daemon does not export `DISPLAY` to TTS children. The wrapper must start or
   find its own Xvfb and set `DISPLAY` itself, as the project helper already does. Do not rely on
   the client's display.
+- **Engine selection**: the Speech settings and the TTS panel list every configured engine. The
+  command engine appears under `VESKSLOP_TTS_NAME` (default "custom engine") and is selectable
+  directly; Auto uses the command engine first. Selecting it hides the language row and shows the
+  `VESKSLOP_TTS_VOICES` list.
+- **Start engine**: the Speech settings have a **Start engine** button (`POST /api/audio/tts/warm`,
+  MCP `start_tts_engine`) that runs one throwaway synthesis to warm the command engine (Xvfb, Wine,
+  host). Keep the wrapper able to handle a short sentence; the warm-up uses "The quick brown fox
+  jumps over the lazy dog." and reports the elapsed milliseconds. Two-pass `loudnorm` must not fail
+  on that input.
+- **Lead-in silence**: Veskslop prepends a short silence at playback time (`VESKSLOP_TTS_LEAD_MS`,
+  default 150 ms) so Discord's voice pipeline is ready before the first syllable. It is added with
+  `adelay` in the player, not in the audio file. The engine needs no change and can keep its
+  5–10 ms edge fades.
 - **Voice declarations**: list only usable IDs in `VESKSLOP_TTS_VOICES`. Veskslop hides the
   espeak list while a custom command is set, so a missing declaration means an empty voice list,
   not a fallback. The list accepts commas or newlines, and the optional `no-pitch` flag tells the
@@ -308,5 +322,8 @@ _Added 2026-09-15._
 - **Flextalk pitch**: confirmed that pitch is a no-op for Keith Bell and Kerry Watson. Mark those
   entries `no-pitch` so users are not offered a control that does nothing. Speed applies to every
   voice and needs no flag.
+  _Engine correction (2026-09-15): the no-op was caused by the speaker registry values being
+  `REG_SZ`; with `REG_DWORD` pitch works and the voices are declared without the flag. See the
+  speed/pitch section._
 - **Licensing**: keep the engine DLLs and voice data local and out of any repository; Veskslop
   never bundles or redistributes them.