fix: satisfy deploy lint gate for S3 compatibility work

- Apply Biome organize-import/formatting fixes across changed S3 files
- Replace remaining string concatenations with template literals for lint
- Make home page inline handlers explicit via window.* and add button types
- Clean S3 auth lint issues with dot-property access and optional chaining
- Keep GetObject proxy and production/S3 SDK tests passing

Verification:
- bun run lint (0 errors, 1 CSS specificity warning)
- S3_SECRET_KEY=<env> bun test test/production-e2e.test.ts (29 pass)
- S3_SECRET_KEY=<env> bun test test/s3-sdk.test.ts (20 pass)
- bun test test/s3-auth.test.ts (5 pass)

src/index.ts

@@ -3,16 +3,16 @@ import { startBot } from './bot';
 import { config } from './env';
 import { handleFileInfo, handleFileRedirect } from './routes/files';
 import { handleHealth } from './routes/health';
+import { handleHome } from './routes/home';
+import { handleS3Request } from './routes/s3';
 import { handleSwaggerHtml, handleSwaggerJson } from './routes/swagger';
 import { handleUpload } from './routes/upload';
-import { handleHome } from './routes/home';
 import { handleWebApiV1 } from './routes/web-api';
-import { handleS3Request } from './routes/s3';
-import { isS3Request } from './utils/s3/auth';
 import { fileInfoCache } from './utils/cache';
 import logger from './utils/logger';
 import { metricsCollector } from './utils/metrics';
 import { cleanupRateLimitCache, withRateLimit } from './utils/rateLimit';
+import { isS3Request } from './utils/s3/auth';
 
 // ─── Auto-run migration at startup ──────────────────────────────────────────
 try {