Configurable paths (config.sh + generated env), vendored speech.h, merge docs

docs/TTS-DESIGN.md

@@ -391,6 +391,43 @@ not need to parse or implement them:
 - Verified on the dev host: `/rate 50` doubles the line duration; `/pitch 150` raises
   the median F0 from 122 Hz to 177 Hz.
 
+### Paths and configuration (standalone)
+
+The engine project is standalone: it has no path dependency on Veskslop and only a
+default sibling-directory dependency on the asset checkouts, both overridable.
+`setup/install.sh` writes `setup/microslopsam.env` with absolute paths; environment
+variables take precedence over that file, so anything can be relocated without editing
+scripts:
+
+| Variable | Default | Meaning |
+| --- | --- | --- |
+| `MICROSLOP_ROOT` | repo root | project root |
+| `MICROSLOP_BUILD` | `$MICROSLOP_ROOT/build` | host binaries, samples |
+| `MICROSLOP_PREFIX` | `~/.wine-microslopsam` | wine prefix (exported as `WINEPREFIX`) |
+| `MICROSLOP_ASSETS` | `../Microsoft-Sam-Mary-Mike-TruVoice-WSAPI4` | SAPI4/MSTTS payloads |
+| `MICROSLOP_FLEXTALK_DIR` | `../flextalk` | Flextalk archive/extraction |
+| `MICROSLOP_SPEECH_H_DIR` | `$MICROSLOP_ROOT/third_party` | `speech.h` include dir (vendored) |
+| `MICROSLOP_DISPLAY` | `:77` | Xvfb display used for Wine |
+| `MICROSLOP_WINE` / `_XVFB` / `_PYTHON` / `_FFMPEG` | tool names | tool overrides |
+
+The wrapper needs only `VESKSLOP_TTS_CMD` to point at its absolute path; it derives
+everything else from its own location plus the env file. `speech.h` is vendored in
+`third_party/`, so the build no longer needs the SDK checkout.
+
+### Merging into Veskslop
+
+This tree is written to survive a copy into the Veskslop repository next to its daemon:
+
+1. Copy `microslopsam/` (or replace the existing copy), then refresh the configuration:
+   `MICROSLOP_UPDATE_ENV=1 microslopsam/setup/install.sh`. Re-running install is
+   idempotent; it rewrites `setup/microslopsam.env` for the new absolute paths.
+2. No daemon changes are required. The env/placeholder contract is unchanged
+   (`VESKSLOP_TTS_*`, `{out}`, `{text_file}`, voice/speed/pitch/expression/profile/
+   highpass/echo/words/word_gap_ms). New features are additive and default off.
+3. Optional Veskslop-side follow-up: a `tts.vox` preference that exports
+   `VESKSLOP_TTS_VOX` (like `words`) and a line in the TTS panel help. The inline
+   `/rate` and `/pitch` controls need no UI work at all.
+
 ### Transport and latency
 
 - Installation is one command: `setup/install.sh` (system dependencies with sudo, wine