Feature/pi research orchestrator

[cacity]

Summary

Describe the user-visible or architectural change and why it is needed.

Verification

• Python tests and Ruff pass.
• Frontend typecheck/build/format pass when UI code changed.
• Rust fmt/check/clippy pass when Tauri code changed.
• New behavior has focused tests.
• CHANGELOG.md is updated for user-visible changes.

Risk and data handling

• No generated binary, model, PDF, database, credential, cookie, or personal path is included.
• New network calls, dependencies, migrations, and privacy/licensing effects are documented.
• Zotero remains read-only and full-text acquisition remains lawful.

Screenshots

Add sanitized before/after images for UI changes. Use synthetic metadata only.