Agent-safe dev/spin lifecycle manager

[SushantGautam]

Summary

Adds an ownership-safe lifecycle manager so agents can start, reuse, stop, restart, reset and uninstall a local stack without killing unrelated processes or resetting real data. Previously there was no safe way for an agent to manage a running dev/spin instance — repeated starts could double-bind ports, and devctl.sh used destructive kill -9/pgrep port-based cleanup.

What changed

• simpleaudit_studio/lifecycle.py (new) — single lifecycle manager shared by dev and spin:
  • Instance identity = sha256 of canonical checkout path (dev) or data dir (spin).
  • File locks: owner.lock (non-blocking, prevents double-start), ports.lock (blocking, serializes port allocation).
  • Ports allocated before Django starts; worktree baseline 8100 (not 8000).
  • _live() validates PID running + create_time + UID to reject PID-reuse false positives.
  • Destructive boundaries: refuses custom SIMPLEAUDIT_DATA_DIR/SIMPLEAUDIT_SQLITE_PATH on reset/uninstall; uv cache cleanup is package-scoped only (never global uv cache clean).
• manage.py — dev dispatches subcommands before django.setup().
• simpleaudit_studio/cli.py — spin gains an action positional; lifecycle dispatch after arg parse.
• infra/management/commands/dev_server.py — bug fix: _stop_web now SIGTERMs the runserver reloader subtree by PID (psutil), never by process group. The reloader tree shares the owner's process group with Caddy/Open WebUI, so a group kill would nuke the whole stack, and terminating only the guard left an orphaned runserver holding the internal port.
• devctl.sh — rewritten as a thin compatibility wrapper; all legacy kill -9/pgrep/lsof port-cleanup removed.
• Docs — docs/development-lifecycle.md, AGENTS.md, README.md.
• Tests — tests/test_lifecycle.py (10 network-free tests).

Verified by actual execution

Check	Method	Result
dev/spin agent-info, status	isolated env	exit 0, no Django import, read-only, no instance record ✅
Repeated start	mock owner harness	2nd start reuses lock, no new port, no kill ✅
Worktree concurrency	2 worktrees, shared state home	non-overlapping ports; stopping A left B untouched ✅
PID-reuse protection	_live() checks	rejects dead/stale PID, accepts valid ✅
Django autoreload	edited template, hit page	hot-reloaded without restart ✅
Full stack live	real dev start	healthz/readyz 200; desktop + mobile render ✅
Reset/uninstall boundaries	disposable data	custom paths refused; uv cleanup package-scoped ✅
dev down orphans	before/after proc+listener check	zero leftover processes/listeners after fix ✅
Genuine git uvx	uvx --from git+...@feat/agent-safe-dev-lifecycle spin …	agent-info/status/uninstall-refusal all correct ✅

Test results

• Ruff: All checks passed!
• Full suite (pytest -m "not embedded_hatchet"): 1283 passed, 4 failed — all 4 pre-existing (fail on base too: catalog metadata drift, retrieval-source INCONCLUSIVE, 2× verify_agentic_audit SystemExit). This branch introduces zero new failures.
• Lifecycle tests: 10/10 pass.

Known limitations (documented in docs/development-lifecycle.md)

• Worker is NOT hot-reloaded — it runs in the owner's main thread (embedded Hatchet singleton requires the main thread). Worker-code changes need a planned restart. Not implementable without a separate worker-process phase.
• uvx may retain shared cached environments that can't be safely identified by package on uninstall.
• Shared-PostgreSQL / multi-instance is out of scope for this single-process manager.

⚠️ Unverified: real data-deletion path of spin uninstall/reset

The genuine data-deletion code path (uninstall/reset against the default spin data dir) was not exercised end-to-end because this machine's ~/.simpleaudit-studio holds ~2.5GB of real user data and the safety boundary forbids resetting it. The refusal path (custom data dir → refused) was verified through a real git-based uvx install. This PR should stay unmerged until spin uninstall/reset cleanup is validated from a genuine uvx installation on a machine where the default data dir is disposable.

Notes

• Stacked on main; does not merge the earlier agentic-demo work.
• No unrelated processes killed, no real user data touched, no paid model APIs used during verification.