feat: Function triggers — schedule, inbound hook, domain events

Migration 00016: function_id on scheduled_jobs/inbound_hooks,
event_pattern on functions, 'event' in the run-trigger enum.

- Jobs deliver to a function instead of HTTP when function_id is set;
  the run's status_code mirrors the process exit code. Clearing the
  field returns the job to URL delivery.
- Inbound hooks gain mode "function" — received body becomes stdin
  payload, acked immediately, run recorded async.
- event_pattern (document.*, *, exact type) fires the function detached
  on matching publishEvent — never blocks realtime/webhook fan-out.
- One executeFunction path serves manual/schedule/hook/event; run rows
  record the trigger source.
- Backend image now ships bun 1.3.14 so Functions work under compose.

Dashboard: job target picker, hook function mode, event-pattern field.

Verified live: job run → success (status_code 0), hook POST → run,
document.created → event run with correct payload.

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

apps/backend/db/queries/jobs.sql

@@ -17,8 +17,9 @@ INSERT INTO core.scheduled_jobs (
   payload,
   enabled,
   next_run_at,
-  created_by_user_id
-) VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9)
+  created_by_user_id,
+  function_id
+) VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10)
 RETURNING *;
 
 -- name: UpdateScheduledJob :one
@@ -30,6 +31,7 @@ SET name = $3,
     next_run_at = $7,
     secret = CASE WHEN $8::boolean THEN $9 ELSE secret END,
     payload = CASE WHEN $10::boolean THEN $11 ELSE payload END,
+    function_id = CASE WHEN $12::boolean THEN $13 ELSE function_id END,
     updated_at = NOW()
 WHERE id = $1
   AND project_id = $2