Settings file, per-job clip folders, faster polling, voices/ rename

Poll interval
  wait_for_completion() polled every 3 s, which quantised every clip to a 3 s
  boundary — across 2075 existing clips, 91% of the gaps landed exactly on a
  multiple of 3 s. It now starts at 0.25 s and backs off to 2 s after 10 s, so
  short clips are picked up immediately without hammering the server on long
  ones. Measured over 34 clips: 4.75 s actual vs 6.35 s under the old poll,
  a 25% cut in TTS wait (~18 min on a 693-clip episode). Runs now print real
  generation time, e.g. "done (4.2s)".

  A WebSocket would remove polling entirely but needs a third-party client,
  which would cost this script its dependency-free property.

settings.ini
  voice, speed, temperature, max_tokens, strip_leading_ms, trailing_fade_ms,
  orig_volume, tts_volume, output_dir and comfy_url moved to an INI file next
  to the script. Precedence is CLI flag > settings.ini > built-in default,
  wired by feeding loaded values in as argparse defaults. --settings FILE
  selects an alternative profile.

  INI rather than TOML (tomllib is 3.11+, this runs on system Python 3.10) or
  JSON (no comments). A missing, partial, malformed or corrupt file degrades to
  built-in defaults with a warning instead of killing a long run.

  Run-specific flags are deliberately excluded: --start, --end, --seed,
  --regen, --rebuild, --resume-from, --embedded-subs, --skip-tts.

Per-job folders
  All state for one video now lives in <output_dir>/clips/<video name>/ —
  clips, tts_input.srt, tts_assembled.flac, embedded_sub.srt and
  video_fragment.mkv. Only <stem>_lektor.mkv stays at the top level.

  tts_input.srt moved with the clips because they are a matched pair: block N
  in the SRT is clip_NNNN.flac. Previously both sat at the top level and each
  new job overwrote the last one's, so rebuilding an older film silently
  paired its clips with the newest film's text. Any past job can now be
  rebuilt. A run against the old flat layout gets an explanatory message.

gudowski/ -> voices/
  VOICE_PROMPTS_DIR is now resolved relative to the script rather than
  hardcoded, so moving the project no longer breaks it. Voice filenames are
  unchanged, so --voice gudowski_short still works.

Docs updated throughout for the new layout, settings file and poll behaviour.

Known issue, not addressed here: with a non-zero --start the voiceover plays
early. extract_video_fragment() stream-copies, so it can only cut on a
keyframe and seeks backwards to it, while TTS timestamps are relative to the
requested start. On S01_E08 at --start 07:40 the nearest earlier keyframe is
458.375 s, putting the voiceover 1.625 s ahead of the picture. Runs with
--start 00:00 are unaffected, since 0 is always a keyframe.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

docs/installation.md

@@ -144,20 +144,30 @@ is not needed; the script drives everything over HTTP.
 
 ## Configuring the script
 
-`lektor_ai_comfy.py` has four constants at the top. If you installed anywhere
-other than the defaults, edit them:
+Most settings live in **`settings.ini`** next to the script — see
+[usage.md](usage.md#settings-file). The backend address in particular:
 
-```python
-COMFY_URL         = "http://127.0.0.1:8189"
-COMFY_OUTPUT_DIR  = Path("/home/lukas/comfy-tts-app/ComfyUI/output")
-COMFY_INPUT_DIR   = Path("/home/lukas/comfy-tts-app/ComfyUI/input")
-VOICE_PROMPTS_DIR = Path("/home/lukas/Programy/lektor_ai/gudowski")
+```ini
+[comfy]
+comfy_url = http://127.0.0.1:8189
 ```
 
-`COMFY_URL` can also be overridden per-run with `--comfy-url`. The two directory
-constants cannot — the script reads generated audio directly from ComfyUI's
-output directory and copies voice references into its input directory, so both
-must be real paths on the same filesystem.
+Two paths remain constants in `lektor_ai_comfy.py`, because the script touches
+ComfyUI's own directories directly rather than over HTTP:
+
+```python
+COMFY_OUTPUT_DIR  = Path("/home/lukas/comfy-tts-app/ComfyUI/output")
+COMFY_INPUT_DIR   = Path("/home/lukas/comfy-tts-app/ComfyUI/input")
+```
+
+Generated audio is read straight out of the output directory and voice
+references are copied into the input directory, so both must be real paths
+reachable from wherever the script runs. **If you installed ComfyUI anywhere
+other than `~/comfy-tts-app`, edit these two lines.** They are also what would
+have to change first to drive a ComfyUI instance on another machine.
+
+A third path, `VOICE_PROMPTS_DIR`, resolves to `voices/` beside the script and
+needs no editing as long as the project stays intact.
 
 The script itself needs no installation. Ensure ffmpeg is present: