Township: Matches list/detail with edit+remove, global Prompts page, --browser

Matches page:
- Lightweight list view (no embedded players); per-match/per-fighter detail
  loads only that item's videos.
- Edit a match: change fighters, environment, short/long targets, and each
  clip's prompt (saved to prompts.json). Fighter-outputs detail edits outcome
  prompts.
- Remove videos: per clip, per final, whole match, single output, or all of a
  fighter's outputs (keeps plan/keyframes for re-render). Traversal-guarded.

Global Prompts page (/prompts):
- Edit the script's global templates — LLM fight/outcome system prompts and the
  static fight-shot + win/ko_win/retire/draw fallback templates. Persisted to
  <out-dir>/prompts_config.json, applied live and re-loaded on every run, with
  reset-to-defaults.

Web UI:
- Only auto-open a browser when --browser is passed (avoids spawning a terminal
  text browser on headless servers).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>