Clean episode titles from linked OneNote notes

[Copilot]

What this changes

• Derives episode titles from matched OneNote notes, removing dates, episode numbers, shorthand, and capitalization errors.
• Applies titles through both prose and set-list linkage while excluding collection pages.

Checklist

• Scoped to this change — no unrelated files swept in
• Directory README.md updated (or none needed)
• AGENTS.md updated if a working rule or convention changed

Playlist data

• Sources touched: none
• make check passes — cache rebuilt, verify.py green, zero-line cache diff
• Overrides changed: none
  Every override edit records a human decision, not an inference
• publication-links.json entries come from real REST responses, not guessed IDs

Tooling

• make lint and make test pass
• A regression test covers any bug fixed in an override path, parser heuristic, or gate

Safety

• No secrets: no .env*, ~/.czarchive.toml, API keys, OAuth tokens, or cookies
• Superseded work moved to discarded/ with a README.md explaining why

• Fixes Update OneNote-linked show titles #61