feat(bottle): random-suffix identity + cli.py resume <identity>

Replaces the cwd-hash identity with a random 5-char base36 suffix
per launch, so two simultaneous `start <agent>` invocations against
the same cwd no longer collide on container names. Each launch is
its own bottle.

State carries metadata: every prepare step writes
~/.claude-bottle/state/<identity>/metadata.json with the
(agent_name, cwd, copy_cwd, started_at) the bottle was launched
with. The new `cli.py resume <identity>` reads this metadata and
re-launches a bottle pinned to the same identity — picking up the
per-bottle Dockerfile (from a prior capability-block apply) and
the transcript snapshot under the same state dir.

- bottle_state.py: bottle_identity(agent_name) drops the cwd param
  and gains a random suffix; BottleMetadata dataclass +
  read/write/metadata_path helpers.
- BottleSpec gains an optional identity field — resume sets it to
  pin the identity; start leaves it empty so prepare mints fresh.
- prepare.py: writes metadata at launch time; uses spec.identity if
  provided (resume) else bottle_identity(agent_name) (fresh start).
- start.py: extracted _launch_bottle from cmd_start so resume can
  share the launch core; prints `./cli.py resume <identity>` hint
  at session end.
- cli/resume.py (new): reads metadata, reconstructs BottleSpec
  with the recorded identity + cwd, delegates to _launch_bottle.
  Errors clearly when no state exists for the given identity.
- cli/__init__.py: registers `resume` in COMMANDS + usage.
- dashboard.py: capability-block approval status line now appends
  the `resume <identity>` hint so the operator can copy-paste the
  rebuild command without leaving the TUI.

Closes the rebuild loop in PRD 0016: agent calls capability-block →
operator approves → bottle torn down with state preserved → status
line shows resume command → operator runs it → replacement bottle
boots with the new Dockerfile and prior transcript.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

claude_bottle/cli/__init__.py

@@ -1,6 +1,6 @@
 """Main CLI dispatcher.
 
-Commands: cleanup, dashboard, edit, info, init, list, start
+Commands: cleanup, dashboard, edit, info, init, list, resume, start
 """
 
 from __future__ import annotations
@@ -15,6 +15,7 @@ from .dashboard import cmd_dashboard
 from .edit import cmd_edit
 from .info import cmd_info
 from .init import cmd_init
+from .resume import cmd_resume
 from .start import cmd_start
 
 cmd_list = _list_mod.cmd_list
@@ -26,6 +27,7 @@ COMMANDS = {
     "info": cmd_info,
     "init": cmd_init,
     "list": cmd_list,
+    "resume": cmd_resume,
     "start": cmd_start,
 }
 
@@ -39,6 +41,7 @@ def usage() -> None:
     sys.stderr.write("  info      print env, skills, and prompt details for a named agent\n")
     sys.stderr.write("  init      interactively create a new agent and add it to claude-bottle.json\n")
     sys.stderr.write("  list      list available agents or active containers\n")
+    sys.stderr.write("  resume    re-launch a bottle by its identity (continues state from PRD 0016)\n")
     sys.stderr.write("  start     boot a container for a named agent and attach an interactive session\n\n")
     sys.stderr.write(f"Run '{PROG} <command> --help' for command-specific usage.\n")