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/utils/s3/auth.ts

@@ -131,8 +131,8 @@ export const verifySignature = async (
   s3SecretKey: string,
   region: string,
 ): Promise<SigV4Result> => {
-  const authHeader = headers['authorization'];
-  if (!authHeader || !authHeader.startsWith('AWS4-HMAC-SHA256')) {
+  const authHeader = headers.authorization;
+  if (!authHeader?.startsWith('AWS4-HMAC-SHA256')) {
     return { isValid: false, credential: null, errorCode: 'AccessDenied' };
   }
 
@@ -276,6 +276,6 @@ export const verifyPresignedUrl = async (
 };
 
 export const isS3Request = (headers: Record<string, string>): boolean => {
-  const auth = headers['authorization'] || '';
+  const auth = headers.authorization || '';
   return auth.startsWith('AWS4-HMAC-SHA256');
 };

src/utils/s3/xml.ts

@@ -12,7 +12,7 @@ const isoDate = (d: Date): string => d.toISOString().replace(/\.\d{3}Z$/, 'Z');
 
 export const listBucketsXml = (
   buckets: { name: string; createdAt: Date }[],
-  requestId: string,
+  _requestId: string,
 ): string => `<?xml version="1.0" encoding="UTF-8"?>
 <ListAllMyBucketsResult xmlns="http://s3.amazonaws.com/doc/2006-03-01/">
   <Buckets>
@@ -39,7 +39,7 @@ export const listBucketResultXml = (
   prefix: string,
   delimiter: string | null,
   nextMarker: string | null,
-  requestId: string,
+  _requestId: string,
 ): string => `<?xml version="1.0" encoding="UTF-8"?>
 <ListBucketResult xmlns="http://s3.amazonaws.com/doc/2006-03-01/">
   <Name>${escapeXml(bucketName)}</Name>
@@ -80,7 +80,7 @@ export const listBucketV2ResultXml = (
   continuationToken: string | null,
   nextContinuationToken: string | null,
   keyCount: number,
-  requestId: string,
+  _requestId: string,
 ): string => `<?xml version="1.0" encoding="UTF-8"?>
 <ListBucketResultV2 xmlns="http://s3.amazonaws.com/doc/2006-03-01/">
   <Name>${escapeXml(bucketName)}</Name>
@@ -131,7 +131,7 @@ export const listPartsXml = (
   parts: { partNumber: number; etag: string; sizeBytes: number; createdAt: Date }[],
   maxParts: number,
   isTruncated: boolean,
-  requestId: string,
+  _requestId: string,
 ): string => `<?xml version="1.0" encoding="UTF-8"?>
 <ListPartsResult xmlns="http://s3.amazonaws.com/doc/2006-03-01/">
   <Bucket>${escapeXml(bucketName)}</Bucket>
@@ -233,12 +233,7 @@ export const s3ErrorResponse = (
 // ─────── DeleteObjects XML parser ───────
 
 export const parseDeleteObjectsBody = (body: string): { keys: string[]; quiet: boolean } => {
-  const keys: string[] = [];
-  const keyRegex = /<Key>([^<]+)<\/Key>/g;
-  let match;
-  while ((match = keyRegex.exec(body)) !== null) {
-    keys.push(match[1]);
-  }
+  const keys = Array.from(body.matchAll(/<Key>([^<]+)<\/Key>/g), (match) => match[1]);
   const quiet = body.includes('<Quiet>true</Quiet>') || body.includes('<Quiet>true ');
   return { keys, quiet };
 };