feat: daemon + agent presence/control (P1-P5 Chorus borrow)

[Vincentwei1021]

Summary

Borrows Chorus's daemon + agent-presence/control features into Synapse, mapped onto Synapse's experiment-centric model. Five phases, all on this branch (47 commits). Lets the frontend wake a local Claude Code, observe live agent connections, and control running turns — all over the existing notification/SSE infrastructure (no new realtime channel).

Phases

P1 — Connection registry & presence data layer. In-memory (agentUuid, host, cwd) registry with online/offline liveness; POST /api/agent-connections/heartbeat (agent) + GET /api/agent-connections (owner-scoped, user); "current executions" reuse Experiment.liveStatus; OpenClaw plugin reports heartbeats.

P2 — synapse daemon. New @synapse-research/synapse-daemon package, bundled into the @synapse-research/synapse CLI as synapse daemon (one-step install). Connects over SSE, and on experiment assignment drives a persistent per-experiment Claude Code conversation (per-turn claude -p --session-id/--resume; conversation persists in claude's own session). Safe-by-default tool posture (--allowedTools mcp__synapse --permission-mode dontAsk; --yolo opt-in). A connected claude_code agent is treated as realtime (dynamic, connection-aware).

P3 — Presence & execution observation UI. @mention online dot + active/idle count; shell-level AgentPresenceProvider (single 15s poll); sidebar "N agents online" pill + popover; ExecutionRow deep-linking to the experiment panel; a Connections section in the /agents detail panel.

P4 — Reverse control + in-experiment instruction injection. From the experiment panel: inject a free-text instruction (writes an audit comment + sends an experiment_instruction notification → daemon resumes the session) and interrupt a running turn (experiment_interrupt → daemon kills the in-flight child via a per-experiment ChildRegistry). User-only routes; recipient derived server-side from the experiment's assignee.

P5 — Session anchoring & human takeover. Session id = experimentUuid (already anchored in P2); panel "Copy session ID" so a human can claude --resume <uuid> in the origin cwd.

Verification

• Unit tests across all phases pass (services, routes, daemon package); daemon pnpm build clean.
• Lint: 0 errors in changed files. i18n: en/zh parity for new presence + control sections.
• End-to-end smoke against a real DB-backed server + real daemon (PGlite-backed branch dev server, real synapse daemon over real SSE): instruction injection → resume turn, second instruction → --resume, audit comment + notifications persisted, interrupt → in-flight child SIGTERM-killed (exit 143) with the daemon surviving.

Release surface (do NOT release yet — this PR is for review)

When released: publish new pkg @synapse-research/synapse-daemon, bump @synapse-research/synapse CLI, rebuild Docker :latest. OpenClaw plugin: only the P1 heartbeat reporter changed. (Holding per request — not releasing.)

🤖 Generated with Claude Code