Use heic-convert for HEIC-to-JPEG conversion

Sharp's prebuilt libvips lacks HEIF codec support. Replace with
heic-convert (pure JS decoder) for reliable HEIC conversion on all
platforms. Existing HEIC files on disk will be converted on-the-fly
when served via /api/files.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

src/app/api/family-upload/route.ts

@@ -3,7 +3,7 @@ import { writeFile, mkdir } from 'fs/promises'
 import path from 'path'
 import { randomUUID } from 'crypto'
 import { getDb } from '@/lib/db'
-import sharp from 'sharp'
+import { convertHeicToJpeg } from '@/lib/heic'
 
 export const runtime = 'nodejs'
 export const maxDuration = 60
@@ -77,7 +77,7 @@ export async function POST(req: NextRequest) {
   let finalExt = ext
   if (mimeType === 'image/heic' || mimeType === 'image/heif') {
     try {
-      finalBuffer = Buffer.from(await sharp(buffer).jpeg({ quality: 90 }).toBuffer())
+      finalBuffer = await convertHeicToJpeg(buffer)
       finalExt = '.jpg'
     } catch {
       // Conversion failed — keep original