feat: generate TypeScript API client from OpenAPI spec and add CI freshness check

Closes leeworks-agents/SPARC#426

- Generate schema.d.ts from committed openapi.json using openapi-typescript
- Rewrite types/index.ts to derive all application types from the generated schema
- Add CI step in both build.yaml and test.yaml to verify schema.d.ts stays in sync
- TypeScript compilation passes with zero errors

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.gitea/workflows/test.yaml

@@ -40,6 +40,16 @@ jobs:
           apk add --no-cache nodejs npm
           cd frontend && npm ci
 
+      - name: Verify generated API types are up to date
+        shell: sh
+        run: |
+          cd frontend && npm run generate:local
+          if ! git diff --quiet src/api/schema.d.ts; then
+            echo "ERROR: src/api/schema.d.ts is out of date. Run 'npm run generate:local' and commit the result."
+            git diff src/api/schema.d.ts
+            exit 1
+          fi
+
       - name: Run TypeScript type check
         shell: sh
         run: |