feat: complete TASK-WP2-06 generation terminal states

apps/api/src/app.ts

@@ -270,12 +270,14 @@ function generationTaskResponse(task: GenerationTaskView) {
   return {
     confirmed_credit_cost: task.confirmedCreditCost,
     created_at: task.createdAt,
+    error_category: task.errorCategory,
     generation_id: task.generationId,
     model_config_version: task.modelConfigVersion,
     model_id: task.modelId,
     project_id: task.projectId,
     prompt: task.prompt,
     ratio: task.ratio,
+    reference_asset_ids: task.referenceAssetIds,
     reference_count: task.referenceCount,
     reserved_credits: task.reservedCredits,
     status: task.status,

apps/api/src/generation-submission.ts

@@ -88,12 +88,16 @@ export type GenerationSubmissionFields = Omit<GenerationSubmissionInput, "newRef
 export interface GenerationTaskView {
   confirmedCreditCost: number;
   createdAt: string;
+  errorCategory: "upstream_timeout" | "upstream_failed" | "safety_rejected" | "model_disabled"
+    | "gateway_balance_insufficient" | "gateway_contract_invalid" | "reference_invalid"
+    | "unknown_retryable" | "unknown_non_retryable" | null;
   generationId: string;
   modelConfigVersion: number;
   modelId: string;
   projectId: string;
   prompt: string;
   ratio: ProjectRatio;
+  referenceAssetIds: string[];
   referenceCount: number;
   reservedCredits: number;
   status: "queued" | "running" | "succeeded" | "failed" | "rejected";
@@ -111,6 +115,7 @@ export interface GenerationUploadSession {
 interface GenerationRow {
   confirmed_credit_cost: number;
   created_at: number;
+  error_category: GenerationTaskView["errorCategory"];
   generation_id: string;
   model_config_version: number;
   model_id: string;
@@ -452,18 +457,21 @@ export class GenerationSubmissionService {
   }
 
   private taskView(row: GenerationRow): GenerationTaskView {
-    const referenceCount = (this.database.prepare("SELECT COUNT(*) AS count FROM generation_reference_snapshots WHERE generation_id = ?")
-      .get(row.generation_id) as { count: number }).count;
+    const referenceAssetIds = (this.database.prepare(`
+      SELECT managed_file_id FROM generation_reference_snapshots WHERE generation_id = ? ORDER BY position
+    `).all(row.generation_id) as Array<{ managed_file_id: string }>).map((entry) => entry.managed_file_id);
     return {
       confirmedCreditCost: row.confirmed_credit_cost,
       createdAt: iso(row.created_at),
+      errorCategory: row.error_category,
       generationId: row.generation_id,
       modelConfigVersion: row.model_config_version,
       modelId: row.model_id,
       projectId: row.project_id,
       prompt: row.prompt,
       ratio: row.ratio,
-      referenceCount,
+      referenceAssetIds,
+      referenceCount: referenceAssetIds.length,
       reservedCredits: row.reserved_credits,
       status: row.status,
       updatedAt: iso(row.updated_at),