Plan

Pure rule parsing and evaluation live in signaltty-agent (screen.rs), compiled once when a manifest loads; regex is the only new dependency (linear-time matching, so user patterns cannot backtrack catastrophically). The server keeps the gate and the transitions: Store records whether the current process has seen a hook, and one Store transition maps a screen state to lifecycle and attention so emits stay paired. A 500 ms server tick reads the visible screen and title of live, unhooked panes whose kind has rules.

Write the red tests first: rule parsing/evaluation unit tests, the Store transition table, then real-PTY integration tests. Record the dependency and the gate in ADR-0024 and the manifest format in docs/07. Gemini (antigravity) reviews the diff; Claude implements and verifies.