fix(render): resolve template id for render jobs + mock-fallback when no .aep

THE bug behind "AEPFilePath is required for real AE render": CreateJob inserted
original_project_id = saved_project_id (VALUES $3,$3), so the claim looked for the
render bundle at templates/{saved_project_id}/ — which never exists. The bundle
lives at templates/{TEMPLATE_id}/. Now original_project_id is resolved from
studio.saved_projects.original_project_id (the template the project was built from).
(Direct-SQL test renders masked this by setting the template id explicitly.)

Also harden the node-agent: Run() falls back to mock render when AEPFilePath is
empty even if AE is installed (previously hard-errored), so a missing/un-promoted
template degrades gracefully instead of failing the job.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

services/node-agent/internal/runner/runner.go

@@ -48,7 +48,14 @@ func Run(ctx context.Context, aePath, workDir string, job *Job, onProgress Progr
 	}
 	outputPath := filepath.Join(outputDir, "output.mp4")
 
-	if aePath == "" {
+	// Mock render when AE isn't installed (aePath empty) OR when this job has no
+	// template project to render (AEPFilePath empty — the template bundle wasn't
+	// uploaded/promoted yet). Mock drives progress+preview to completion so the job
+	// doesn't hard-fail; a real render requires both AE and a downloaded .aep.
+	if aePath == "" || job.AEPFilePath == "" {
+		if aePath != "" && job.AEPFilePath == "" {
+			log.Printf("[job %s] no template .aep available — falling back to mock render", job.JobID)
+		}
 		return mockRender(ctx, job, outputPath, onProgress, onPreview)
 	}
 	return aeRender(ctx, aePath, job, outputPath, onProgress, onPreview)

services/render/internal/db/db.go

@@ -430,7 +430,11 @@ func (s *Store) CreateJob(ctx context.Context, userID, tenantID uuid.UUID, req *
 		  (tenant_id, user_id, saved_project_id, original_project_id,
 		   priority_queue, step, price_type, quality, resolution, r_height,
 		   frame_rate, is_60_fps, duration_sec, mode, tell_me_when_done, region)
-		VALUES ($1, $2, $3, $3,
+		VALUES ($1, $2, $3,
+		        -- original_project_id = the TEMPLATE the saved project was created from
+		        -- (the render bundle lives at templates/{original_project_id}/). Fall back
+		        -- to the saved-project id only if the lookup is somehow null.
+		        COALESCE((SELECT original_project_id FROM studio.saved_projects WHERE id = $3), $3),
 		        'paid'::render_priority_queue, 'Queued'::render_step, $4::price_kind,
 		        $5::render_quality, $6, 1080, $7, COALESCE($8, FALSE),
 		        0, 'FIX', $9, $10)