feat(11-01): run job workers in serve and queue:work, add queue:clear

- Manager gains the apparatus JobManager surface: StartJob, UpdateJobState,
  UpdateMetadata, FailJob, CancelJob (is_canceled + STOPPED + River JobCancel),
  StopJob (STOPPED only), CheckIfCanceled and GetMetadata, all raw column
  writes so updated_at is untouched
- serve starts the in-process worker unless queue.work_in_serve is false and
  stops it on shutdown; an app without jobs gets an idle worker
- queue:work runs a foreground worker with repeatable --queue filters;
  queue:clear deletes available, scheduled and retryable jobs of one queue
- the generated main appends conga.RuntimeCommands; summer delegates
  queue:work and queue:clear; make:job scaffolds a conga.Job

cmd/summer/main_test.go

@@ -19,7 +19,7 @@ func TestToolCommandNames(t *testing.T) {
 	for _, c := range toolCommands() {
 		names = append(names, c.Name)
 	}
-	for _, want := range []string{"build", "make:plugin", "make:model", "make:migration", "make:command", "make:job", "make:admin-controller", "plugin:add", "dev", "migrate", "migrate:rollback", "migrate:status", "serve"} {
+	for _, want := range []string{"build", "make:plugin", "make:model", "make:migration", "make:command", "make:job", "make:admin-controller", "plugin:add", "dev", "migrate", "migrate:rollback", "migrate:status", "serve", "queue:work", "queue:clear"} {
 		if !slices.Contains(names, want) {
 			t.Fatalf("missing %s in %v", want, names)
 		}