feat: remote file access, running-scoped discovery, replay collapse, release 0.7.0

[william0wang]

Summary

Everything since 0.5.1, released as 0.7.0 (0.6.0 features folded in — never published separately).

Remote access

• Read-only session file access over hub-proxied HTTP (/fs/list, /fs/file), session-cwd scoped, byte/line windowing (ADR-0004).
• Running-scoped discovery: two gates (currently running + accessible), advertised ids stay the editor-facing ACP session ids so a remote attach shares the live stream; hub dedupes sessions across instances by freshest updatedAt.
• Removed the 0.5.1 heartbeat availability probe — live measurements disproved its premise (session/messages 35–120ms at 3MB; no takeover invalidation).

Replay

• Replayed tool calls carry state input/output as expandable content blocks.
• Harness plumbing replays as collapsed tool_call cards: context handoffs, textualized tool transcripts, <task-notification> blocks (decoded summary as title), and — new — compact_summary messages under the store's own title (Compact summary), so compaction points (auto-compact included) survive reload.
• Hidden harness plumbing (transcriptVisibility: "hidden", e.g. plan-file references) no longer leaks as user message walls.

Live mirroring

• session/prompt is echoed to every OTHER attached client as user_message_chunk (uprompt_ prefix), sender excluded — a turn driven from one end now arrives on the other with the message that started it. Verified live: thought/text/tool updates already broadcast to all clients, direct and through the hub proxy.

Test plan

• 626/626 tests (7 new: compact card, hidden skip, notifyOthers exclusion, prompt echo)
• typecheck / lint / prettier / build
• Live-probed against a real backend session (compacted twice): "Compact summary" card emits, plan-file leak gone, tool transcripts unchanged
• Passive WS listeners (direct + via hub) captured full broadcast incl. agent_thought_chunk frames