fix: production bugs + comprehensive production e2e tests

Fixes:
- RowList bug: postgres.js returns array directly, not {rows}. Fix in
  buckets.ts, files-ext.ts, multipart.ts (3 files, 8 functions)
- S3 ListBuckets routing: GET / was intercepted by handleHome route
- Presigned URL detection: isS3Request() only checked Authorization header
- FK constraint on bucket delete: cascade-delete files & multipart rows first
- docker-compose.yml: pass S3_ACCESS_KEY / S3_SECRET_KEY to container
- Dockerfile: copy home.html to runner stage for handleHome

Tests:
- test/production-e2e.test.ts: 29 tests (11 Web API + 18 S3 SigV4)
  All pass against https://upload.asepharyana.my.id
- Creates and cleans up real buckets/objects on production

Dockerfile

@@ -21,6 +21,7 @@ WORKDIR /usr/src/app
 # Copy built files, schema, and package.json
 COPY --from=builder /usr/src/app/dist/index.js ./dist/index.js
 COPY --from=builder /usr/src/app/dist/migrate.js ./dist/migrate.js
+COPY --from=builder /usr/src/app/src/home.html ./home.html
 COPY schema.sql ./
 COPY package.json ./