feat: avatar upload via presigned PUT URL flow

- Go scraper: add PresignAvatarUploadURL/PresignAvatarURL/DeleteAvatar to
  Store interface, implement on HybridStore+MinioClient, register
  GET /api/presign/avatar-upload/{userId} and /api/presign/avatar/{userId}
- SvelteKit: replace direct AWS S3 SDK in minio.ts with presign calls to
  the Go scraper; rewrite avatar +server.ts (POST=presign, PATCH=record key)
- iOS: rewrite uploadAvatar() as 3-step presigned PUT flow; refactor
  chip components into shared ChipButton in CommonViews.swift

ui/src/lib/server/minio.ts

@@ -9,40 +9,15 @@
 import { env } from '$env/dynamic/private';
 import { env as pubEnv } from '$env/dynamic/public';
 import { log } from '$lib/server/logger';
-import { S3Client, PutObjectCommand, DeleteObjectCommand, HeadObjectCommand, GetObjectCommand } from '@aws-sdk/client-s3';
-import { getSignedUrl } from '@aws-sdk/s3-request-presigner';
 
 const SCRAPER_URL = env.SCRAPER_API_URL ?? 'http://localhost:8080';
 // Public MinIO URL — used to rewrite presigned URLs so the browser can reach MinIO directly.
 // In docker-compose this would differ from the internal endpoint.
 const MINIO_PUBLIC_URL = pubEnv.PUBLIC_MINIO_PUBLIC_URL ?? 'http://localhost:9000';
 
-// MinIO direct client (for avatar uploads — not routed through Go scraper)
-const MINIO_ENDPOINT = env.MINIO_ENDPOINT ?? 'localhost:9000';
-const MINIO_ACCESS_KEY = env.MINIO_ACCESS_KEY ?? 'admin';
-const MINIO_SECRET_KEY = env.MINIO_SECRET_KEY ?? 'changeme123';
-const MINIO_USE_SSL = (env.MINIO_USE_SSL ?? 'false').toLowerCase() === 'true';
-const BUCKET_AVATARS = env.MINIO_BUCKET_AVATARS ?? 'libnovel-avatars';
-
-function makeS3Client(): S3Client {
-	return new S3Client({
-		endpoint: `${MINIO_USE_SSL ? 'https' : 'http'}://${MINIO_ENDPOINT}`,
-		region: 'us-east-1', // MinIO ignores region but SDK requires one
-		credentials: { accessKeyId: MINIO_ACCESS_KEY, secretAccessKey: MINIO_SECRET_KEY },
-		forcePathStyle: true // MinIO requires path-style URLs
-	});
-}
-
 // ─── Avatar helpers ───────────────────────────────────────────────────────────
 
-const AVATAR_EXTS = ['jpg', 'png', 'webp', 'gif'] as const;
-type AvatarExt = (typeof AVATAR_EXTS)[number];
-
-function avatarKey(userId: string, ext: AvatarExt): string {
-	return `avatars/${userId}.${ext}`;
-}
-
-function extFromMime(mime: string): AvatarExt {
+function extFromMime(mime: string): string {
 	if (mime.includes('png')) return 'png';
 	if (mime.includes('webp')) return 'webp';
 	if (mime.includes('gif')) return 'gif';
@@ -50,32 +25,19 @@ function extFromMime(mime: string): AvatarExt {
 }
 
 /**
- * Upload an avatar image buffer to MinIO.
- * Deletes any existing avatar for this user first, then stores the new one.
- * Returns the MinIO object key (e.g. "avatars/abc123.jpg").
+ * Returns a short-lived presigned PUT URL for uploading an avatar directly to MinIO,
+ * along with the object key to record in PocketBase after upload completes.
+ * Routed through the Go scraper which holds MinIO credentials.
  */
-export async function putAvatar(userId: string, data: Uint8Array, mimeType: string): Promise<string> {
+export async function presignAvatarUploadUrl(userId: string, mimeType: string): Promise<{ uploadUrl: string; key: string }> {
 	const ext = extFromMime(mimeType);
-	const s3 = makeS3Client();
-
-	// Delete old avatars (all extensions) to avoid stale objects
-	await Promise.all(
-		AVATAR_EXTS.map((e) =>
-			s3.send(new DeleteObjectCommand({ Bucket: BUCKET_AVATARS, Key: avatarKey(userId, e) })).catch(() => {})
-		)
-	);
-
-	const key = avatarKey(userId, ext);
-	await s3.send(
-		new PutObjectCommand({
-			Bucket: BUCKET_AVATARS,
-			Key: key,
-			Body: data,
-			ContentType: mimeType
-		})
-	);
-	log.info('minio', 'avatar uploaded', { userId, key });
-	return key;
+	const res = await fetch(`${SCRAPER_URL}/api/presign/avatar-upload/${encodeURIComponent(userId)}?ext=${ext}`);
+	if (!res.ok) {
+		const body = await res.text().catch(() => '');
+		throw new Error(`presign avatar upload failed: ${res.status} ${body}`);
+	}
+	const data = (await res.json()) as { upload_url: string; key: string };
+	return { uploadUrl: data.upload_url, key: data.key };
 }
 
 /**
@@ -83,25 +45,14 @@ export async function putAvatar(userId: string, data: Uint8Array, mimeType: stri
  * Returns null if no avatar exists.
  */
 export async function presignAvatarUrl(userId: string): Promise<string | null> {
-	const s3 = makeS3Client();
-	for (const ext of AVATAR_EXTS) {
-		const key = avatarKey(userId, ext);
-		try {
-			await s3.send(new HeadObjectCommand({ Bucket: BUCKET_AVATARS, Key: key }));
-			// Object exists — generate presigned URL using public endpoint
-			const pubS3 = new S3Client({
-				endpoint: MINIO_PUBLIC_URL,
-				region: 'us-east-1',
-				credentials: { accessKeyId: MINIO_ACCESS_KEY, secretAccessKey: MINIO_SECRET_KEY },
-				forcePathStyle: true
-			});
-			const url = await getSignedUrl(pubS3, new GetObjectCommand({ Bucket: BUCKET_AVATARS, Key: key }), { expiresIn: 86400 });
-			return url;
-		} catch {
-			// not found or error — try next extension
-		}
+	const res = await fetch(`${SCRAPER_URL}/api/presign/avatar/${encodeURIComponent(userId)}`);
+	if (res.status === 404) return null;
+	if (!res.ok) {
+		const body = await res.text().catch(() => '');
+		throw new Error(`presign avatar failed: ${res.status} ${body}`);
 	}
-	return null;
+	const data = (await res.json()) as { url: string };
+	return data.url ?? null;
 }
 
 /**

ui/src/lib/server/pocketbase.ts

@@ -801,9 +801,13 @@ export async function revokeAllUserSessions(userId: string): Promise<void> {
  */
 export async function updateUserAvatarUrl(userId: string, avatarUrl: string): Promise<void> {
 	const token = await getToken();
-	await fetch(`${PB_URL}/api/collections/app_users/records/${userId}`, {
+	const res = await fetch(`${PB_URL}/api/collections/app_users/records/${userId}`, {
 		method: 'PATCH',
 		headers: { Authorization: `Bearer ${token}`, 'Content-Type': 'application/json' },
 		body: JSON.stringify({ avatar_url: avatarUrl })
 	});
+	if (!res.ok) {
+		const body = await res.text().catch(() => '');
+		throw new Error(`updateUserAvatarUrl failed: ${res.status} ${body}`);
+	}
 }