Cookbook scheduler + serve: schedule via Tasks, Stop verifies kill, Ollama auto port-pick

- Schedule cookbook serves through the existing ScheduledTask system: the
  serve preset gets a ^ button next to Launch that opens a daily/hourly/
  weekly form mirroring the admin-switch style; the schedule action runs
  action_cookbook_serve, which delegates to /api/model/serve and stamps
  the resulting task with _scheduledStopAtMs. A background
  cookbook_serve_lifecycle loop ticks every 60s and kills any serve
  whose window has ended, also dropping the auto-registered endpoint
  so the model picker doesn't keep pointing at a dead server.
- Stop and remove on a Running serve now awaits the SSH/tmux kill,
  re-checks tmux has-session, and surfaces an error toast (leaving the
  row) when the kill failed. Previously fire-and-forget, so a failed
  SSH/tmux call silently left the live serve running while the row
  vanished from the UI.
- Cookbook tasks/status orphan-adoption sweep no longer requires the
  serve-/cookbook- session-id prefix; any tmux session whose pane is
  running a known model-server process gets auto-pulled into Running.
  Without this loosening, a cookbook-launched serve whose tmux id
  fell back to a bare number was invisible — you couldn't see it,
  let alone stop it.
- Ollama serve always launches a fresh process under cookbook's tmux
  (no more monitor-mode reattach to a systemd/Docker ollama Stop can't
  reach). The handler pre-picks a free port by probing the target
  host over SSH and mutates req.cmd's OLLAMA_HOST so the runner script
  AND the auto-registered endpoint agree on the same bind port.
- Auto-register uses host.docker.internal (when running inside Docker)
  instead of localhost, matching the URL /setup adds for Ollama by
  hand. Local cookbook serves now produce a chat-reachable endpoint
  on first launch.
- Cascade-delete: removing a scheduled cookbook task also deletes any
  linked calendar event (cookbook_task_id marker in the description).
- Tasks list groups cookbook_serve under a "Cookbook" category that
  sorts above the rest, so scheduler-launched serves are easy to find.

src/task_scheduler.py

@@ -1018,6 +1018,10 @@ class TaskScheduler:
             kwargs = {"owner": task.owner, "task_name": task.name, "progress_cb": _progress}
             if task.action in ("run_script", "run_local", "ssh_command") and task.prompt:
                 kwargs["script" if task.action in ("run_script", "run_local") else "command"] = task.prompt
+            # cookbook_serve carries its JSON config in task.prompt — feed it
+            # through as `command` so action_cookbook_serve can json.loads it.
+            elif task.action == "cookbook_serve" and task.prompt:
+                kwargs["command"] = task.prompt
             result, success = await action_fn(**kwargs)
             return result, success
         except TaskNoop: