fix: serve frontend assets below admin path

Dockerfile

@@ -6,6 +6,7 @@ RUN corepack enable
 COPY web/package.json web/pnpm-lock.yaml web/pnpm-workspace.yaml ./
 RUN pnpm install --frozen-lockfile
 COPY web/ ./
+ENV VITE_PUBLIC_PATH=/admin/
 RUN pnpm run build
 
 # ---- Stage 2: build the Go backend ----

tests/test_deployment_contract.py

@@ -19,6 +19,7 @@ class DeploymentContractTest(unittest.TestCase):
         dockerfile = (ROOT / "Dockerfile").read_text()
 
         self.assertIn("RUN pnpm run build", dockerfile)
+        self.assertIn("VITE_PUBLIC_PATH=/admin/", dockerfile)
         self.assertIn("COPY --from=web-builder /web/dist ./web/dist", dockerfile)
         self.assertIn("COPY --from=web-builder /web/dist /app/web/dist", dockerfile)
         self.assertIn("EXPOSE 6061", dockerfile)