Cookbook scheduler: calendar events drive model serve windows (experimental, feature-flagged)

Add a calendar-driven scheduler so a user can pick a model in Cookbook, click "Schedule…" instead of "Launch", choose time windows + days of the week + (optional) end date, and have Odysseus auto-launch the serve when the window starts and hard-kill it when the window ends. The calendar IS the source of truth — events on a designated calendar are interpreted as serve schedules, so editing the event in the calendar UI immediately changes the schedule.

Whole feature is gated by setting `cookbook_scheduler_enabled` (default False). Disabling the setting silences the reconciler and the API refuses requests; setting + three new files = entire surface, easy to revert.

New files:
  - src/cookbook_scheduler.py — background reconciler: ticks every 60s, reads next ±90s of calendar events on the designated calendar, launches/kills serves to match. Honors "refuse if GPUs busy" (skips with reason, no retry). Adopts pre-existing manual serves matching the event's model so window-end cleanup still applies. Tags scheduler-owned tasks with `_scheduledBy: <event_uid>` so it never kills serves it doesn't own.
  - routes/cookbook_schedule_routes.py — POST /api/cookbook/schedule/from-cookbook builds RRULE+ICS events from the modal's input (model, slots[], days[], until). GET /upcoming returns the next 24h with per-event status (scheduled / running / adopted / skipped / failed / ended) for the UI. POST /reconcile-now manually kicks the reconciler.
  - static/js/cookbookSchedule.js — Schedule button click handler + modal. Daily/hourly time slot picker, multi-slot ("+ add another time slot"), weekday chips with Weekdays/Weekend/Every-day quicksets, optional Until date. Calls /from-cookbook on save. Whole module is a single IIFE; deleting the file plus its <script> tag removes the UI surface.

Existing files touched (minimal):
  - app.py: register the new router + add the reconcile loop as a startup task (~10 lines, all in one block). Reconcile loop checks the feature flag on every tick, so leaving it running with the flag off costs ~one settings lookup per minute.
  - static/index.html: one new <script> tag for cookbookSchedule.js.
  - static/js/cookbookServe.js: add a "Schedule…" button next to the existing Launch button. Hidden by default; cookbookSchedule.js reveals it after confirming the feature flag is on.
  - static/style.css: ~80 lines for the modal styles (mobile-aware via @media).

User choices baked in:
  - Calendar events are the source of truth.
  - Refuse to launch if GPUs busy (skip + log reason in scheduler.events[uid].reason).
  - Hard kill at event end.
  - No retry on a skipped event within the window.
  - Multi-slot per day supported (one calendar event per slot, shared RRULE).
  - Pre-existing manual serves get adopted at window start so they're killed at end.

Known follow-ups (not in this commit):
  - Settings UI to pick the schedule calendar + toggle the feature flag.
  - Calendar event color/badge for status (running/skipped/failed).
  - "Lazy launch on first request" — currently launches at event start. Replacing _launch_serve with a proxy that defers vllm until the first chat request is a contained future change.

app.py

@@ -640,6 +640,14 @@ app.include_router(setup_shell_routes())
 from routes.cookbook_routes import setup_cookbook_routes
 app.include_router(setup_cookbook_routes())
 
+# Cookbook scheduler — calendar-driven serve windows.
+# Feature-flagged on the `cookbook_scheduler_enabled` setting (default
+# off); disabling the setting silences the reconciler and the API
+# refuses requests. Delete this block + src/cookbook_scheduler.py +
+# routes/cookbook_schedule_routes.py to remove the feature entirely.
+from routes.cookbook_schedule_routes import setup_cookbook_schedule_routes
+app.include_router(setup_cookbook_schedule_routes())
+
 # Hardware model fitting (cookbook "What Fits?" tab)
 from routes.hwfit_routes import setup_hwfit_routes
 app.include_router(setup_hwfit_routes())
@@ -1061,6 +1069,14 @@ async def _startup_event():
                 logger.warning(f"Nightly skill audit failed: {e}")
 
     _startup_tasks.append(asyncio.create_task(_skill_audit_nightly_loop()))
+
+    # Cookbook scheduler reconcile loop. Internally checks the
+    # cookbook_scheduler_enabled setting on every tick, so leaving this
+    # task running with the feature disabled costs ~one settings lookup
+    # per minute. Remove this line to dispose of the feature.
+    from src.cookbook_scheduler import reconcile_loop as _cookbook_reconcile_loop
+    _startup_tasks.append(asyncio.create_task(_cookbook_reconcile_loop()))
+
     logger.info("Application startup complete")
 
 async def _shutdown_event():