Validate Zed Assistant adapter against current Zed

[study8677]

The new Zed adapter (src/retitle/adapters/zed.py) was added in v0.5.0 with a best-guess at the Zed Assistant storage layout. Stored conversations:

• macOS: ~/Library/Application Support/Zed/conversations/<uuid>.json
• Linux: ~/.config/Zed/conversations/<uuid>.json

We assumed:

{
  "summary": "auto-generated title",
  "messages": [{ "role": "user", "text": "..." }, { "role": "assistant", "text": "..." }],
  "project": { "path": "/path/to/cwd" }
}

Need a Zed user to validate. Specifically:

1. Does the path still resolve in the current Zed (Zed v0.16+ may have moved storage; some flavours use SQLite-backed threads now)
2. Is the title field really called summary? If not, what?
3. Are messages messages[*].role + messages[*].text? Or some other shape?
4. Does Zed reload from disk on next launch if we rewrite the title? Or does it cache and overwrite?

A redacted top-level jq 'keys' of one conversation file is enough to start. PRs welcome.