feat(04-02): add togglePin and updateDueDate form actions

- Add togglePin action to toggle entry.pinned boolean state
- Add updateDueDate action to set/clear entry.dueDate
- Both actions validate entry exists before updating

src/routes/+page.server.ts

@@ -220,6 +220,45 @@ export const actions: Actions = {
 		// Delete from database
 		imageRepository.delete(imageId);
 
+		return { success: true };
+	},
+
+	togglePin: async ({ request }) => {
+		const formData = await request.formData();
+		const id = formData.get('id')?.toString();
+
+		if (!id) {
+			return fail(400, { error: 'Entry ID is required' });
+		}
+
+		const existing = entryRepository.getById(id);
+		if (!existing) {
+			return fail(404, { error: 'Entry not found' });
+		}
+
+		// Toggle pinned state
+		entryRepository.update(id, { pinned: !existing.pinned });
+
+		return { success: true };
+	},
+
+	updateDueDate: async ({ request }) => {
+		const formData = await request.formData();
+		const id = formData.get('id')?.toString();
+		const dueDate = formData.get('dueDate')?.toString() || null;
+
+		if (!id) {
+			return fail(400, { error: 'Entry ID is required' });
+		}
+
+		const existing = entryRepository.getById(id);
+		if (!existing) {
+			return fail(404, { error: 'Entry not found' });
+		}
+
+		// Update due date (empty string becomes null)
+		entryRepository.update(id, { dueDate: dueDate || null });
+
 		return { success: true };
 	}
 };