F-mcp-terminal-sync: wait_for_status + read_terminal (act -> wait -> observe)

[bastien-gallay]

Summary

F-mcp-terminal-sync — the "rich" layer: perception + synchronisation over
a session's terminal. wait_for_status and read_terminal. This is what turns
fire-and-forget orchestration into a browser-grade act → wait → observe loop.

Child of the F-mcp-control-surface 🧬 split
(.personal/feature-torture/reports/F-mcp-control-surface.md; brainstorm
brainstorm/20260713-mcp-agent-terminal-interaction.md). Analogy: terminal =
"page", OSC status = "load-state", PTY text = "DOM text".

Scope

• wait_for_status(session, Idle|Attention) — built on the already-shipped
  OSC status machine (SessionStatus::Busy|Attention|Idle). Always
  timeout-bounded + a max-wait cap (a session that never idles must not hang
  the caller — Q7).
• read_terminal(session) — the focused/target PTY visible text, generalised
  from the CaptureDump per session.
• Deliberately out: wait_for_text(pattern) (poll-raced) and a selector
  DSL — YAGNI, a stable handle + status suffice (per the FT report).

Relationships

• Parent epic: Expose termherd's control surface as an MCP server (config + orchestration) #90
• Depends on F-mcp-live-bridge (live transport + stable handle).
• Enables F-mcp-agent-loop.

Labels: enhancement, P2