feat(03-02): add uploadImage form action with thumbnail generation

- Add uploadImage action that handles multipart file uploads
- Validate file type and entry existence before processing
- Generate thumbnail using Sharp with EXIF rotation
- Save original and thumbnail to filesystem
- Store image metadata in database
- Return entries with their images attached from load function

src/routes/+page.server.ts

@@ -1,13 +1,21 @@
 import type { PageServerLoad, Actions } from './$types';
 import { fail } from '@sveltejs/kit';
-import { entryRepository } from '$lib/server/db/repository';
+import { entryRepository, imageRepository } from '$lib/server/db/repository';
+import { saveOriginal, saveThumbnail, ensureDirectories } from '$lib/server/images/storage';
+import { generateThumbnail } from '$lib/server/images/thumbnails';
 
 export const load: PageServerLoad = async ({ url }) => {
 	const showCompleted = url.searchParams.get('showCompleted') === 'true';
 	const entries = entryRepository.getOrdered({ showCompleted });
 
+	// Attach images to each entry
+	const entriesWithImages = entries.map((entry) => ({
+		...entry,
+		images: imageRepository.getByEntryId(entry.id)
+	}));
+
 	return {
-		entries,
+		entries: entriesWithImages,
 		showCompleted
 	};
 };
@@ -127,5 +135,58 @@ export const actions: Actions = {
 		entryRepository.update(id, { status: newStatus });
 
 		return { success: true };
+	},
+
+	uploadImage: async ({ request }) => {
+		const formData = await request.formData();
+		const file = formData.get('image') as File;
+		const entryId = formData.get('entryId') as string;
+
+		if (!file || file.size === 0) {
+			return fail(400, { error: 'No file uploaded' });
+		}
+
+		if (!entryId) {
+			return fail(400, { error: 'Entry ID required' });
+		}
+
+		// Verify entry exists
+		const entry = entryRepository.getById(entryId);
+		if (!entry) {
+			return fail(404, { error: 'Entry not found' });
+		}
+
+		// Validate image type
+		if (!file.type.startsWith('image/')) {
+			return fail(400, { error: 'File must be an image' });
+		}
+
+		const ext = file.name.split('.').pop()?.toLowerCase() || 'jpg';
+		const buffer = Buffer.from(await file.arrayBuffer());
+
+		try {
+			await ensureDirectories();
+
+			// Generate and save thumbnail
+			const thumbnailBuffer = await generateThumbnail(buffer);
+
+			// Save to database to get ID
+			const image = imageRepository.create({
+				entryId,
+				filename: file.name,
+				ext
+			});
+
+			// Save original
+			await saveOriginal(image.id, ext, buffer);
+
+			// Save thumbnail
+			await saveThumbnail(image.id, thumbnailBuffer);
+
+			return { success: true, imageId: image.id };
+		} catch (err) {
+			console.error('Upload error:', err);
+			return fail(500, { error: 'Failed to save image' });
+		}
 	}
 };