Expose lifecycle-aware agent tree with live terminal state

[lawrencecchen]

Fixes #7867
Supersedes #7869 and #8309

Summary

• Add a provider-neutral agent session registry with durable runs, process generations, restore authority, parent/child and fork edges, workloads, bounded history, and runtime ownership.
• Add cmux agents list and cmux agents tree; retain cmux sessions as a compatibility alias.
• Reconcile hook lifecycle with cached terminal process/state observations without terminal capture or UI-thread filesystem work.
• Make restore, fork, hibernation, and completion fail closed on stale, ambiguous, corrupt, unavailable, or non-replayable session evidence.
• Support hook-backed providers and terminal-only detection while preserving provider-specific lifecycle authority.
• Bound registry import, legacy discovery, graph projection, transcript lookup, executable validation, and CLI rendering work.

Testing

• cmux-unit build-for-testing passes on the current head.
• Tagged macOS fleet build a7970 passes on the current head: https://github.com/manaflow-ai/cmux/actions/runs/29674242597
• Regression coverage includes registry migration/corruption, authority recovery, PID reuse, runtime scoping, lifecycle races, CLI list/tree projection, bounded scans, hibernation teardown, provider replay contracts, and executable/shebang availability.
• Project normalization, test wiring, workspace package grouping, localization JSON parsing, English/Japanese localization coverage, and diff whitespace checks pass.

Demo video

Not included. The CLI path is deterministic and is covered by tagged preflight plus behavior-level tests.

Review trigger

Review the current head after required checks finish.

Checklist

• Behavior-level regressions precede their fixes where applicable.
• User-facing strings include English and Japanese localizations.
• App target and test bundle compile.
• Current main is merged cleanly.
• Required checks pass on the pushed head.
• Dogfood approval received.

Summary by CodeRabbit

• New Features

  • Added cmux agents list and cmux agents tree for inspecting agent sessions, relationships, activity, workloads, and lifecycle state.
  • Added JSON output, filtering, history views, depth limits, and bounded result handling.
  • Added runtime-aware session scoping to distinguish current and historical sessions.
  • Added workload tracking for background tasks, monitors, scheduled work, tools, and subagents.
  • Added improved hibernation, restoration, fork, completion, and interruption handling.
  • Added Copilot hook support and expanded agent integrations.

• Bug Fixes

  • Improved notification ownership, stale-session protection, process tracking, and lifecycle race handling.
  • Improved resilience when session data is malformed, duplicated, or incomplete.