feat(storage): improve shared-storage robustness, scalability, and DX

- Fix exists() to only catch 404/NotFound, rethrow real errors
- Add downloadStream() for memory-efficient large file downloads
- Add uploadMultipart() using @aws-sdk/lib-storage for large files
- Add automatic pagination to list() via continuation tokens
- Add CDN URL support (cdnUrl in BucketConfig, getCdnUrl() method)
- Reduce factory boilerplate with generic createStorage() function
- Add MinIO lifecycle rules for tmp/ prefixes (chat 90d, calendar 30d, picture 7d)
- Add vitest setup with 56 tests covering client, factory, and utils

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

packages/shared-storage/src/utils.spec.ts

@@ -0,0 +1,91 @@
+import { describe, it, expect } from 'vitest';
+import {
+	generateFileKey,
+	generateUserFileKey,
+	getContentType,
+	validateFileSize,
+	validateFileExtension,
+} from './utils';
+
+describe('generateFileKey', () => {
+	it('generates a UUID-based key with extension', () => {
+		const key = generateFileKey('photo.png');
+		expect(key).toMatch(/^[0-9a-f-]{36}\.png$/);
+	});
+
+	it('includes folder path', () => {
+		const key = generateFileKey('image.jpg', 'uploads', '2024');
+		expect(key).toMatch(/^uploads\/2024\/[0-9a-f-]{36}\.jpg$/);
+	});
+
+	it('handles files without extension', () => {
+		const key = generateFileKey('Dockerfile');
+		expect(key).toMatch(/^[0-9a-f-]{36}$/);
+	});
+});
+
+describe('generateUserFileKey', () => {
+	it('generates a user-scoped key', () => {
+		const key = generateUserFileKey('user-123', 'avatar.png');
+		expect(key).toMatch(/^users\/user-123\/[0-9a-f-]{36}\.png$/);
+	});
+
+	it('includes subfolder when provided', () => {
+		const key = generateUserFileKey('user-123', 'photo.jpg', 'avatars');
+		expect(key).toMatch(/^users\/user-123\/avatars\/[0-9a-f-]{36}\.jpg$/);
+	});
+});
+
+describe('getContentType', () => {
+	it.each([
+		['image.jpg', 'image/jpeg'],
+		['image.jpeg', 'image/jpeg'],
+		['image.png', 'image/png'],
+		['image.gif', 'image/gif'],
+		['image.webp', 'image/webp'],
+		['image.svg', 'image/svg+xml'],
+		['doc.pdf', 'application/pdf'],
+		['song.mp3', 'audio/mpeg'],
+		['video.mp4', 'video/mp4'],
+		['data.json', 'application/json'],
+		['archive.zip', 'application/zip'],
+	])('returns correct type for %s', (filename, expected) => {
+		expect(getContentType(filename)).toBe(expected);
+	});
+
+	it('returns octet-stream for unknown extensions', () => {
+		expect(getContentType('file.xyz')).toBe('application/octet-stream');
+	});
+
+	it('is case-insensitive', () => {
+		expect(getContentType('FILE.PNG')).toBe('image/png');
+	});
+});
+
+describe('validateFileSize', () => {
+	it('returns true when within limit', () => {
+		expect(validateFileSize(5 * 1024 * 1024, 10)).toBe(true);
+	});
+
+	it('returns true at exact limit', () => {
+		expect(validateFileSize(10 * 1024 * 1024, 10)).toBe(true);
+	});
+
+	it('returns false when over limit', () => {
+		expect(validateFileSize(11 * 1024 * 1024, 10)).toBe(false);
+	});
+});
+
+describe('validateFileExtension', () => {
+	it('returns true for allowed extension', () => {
+		expect(validateFileExtension('photo.png', ['.png', '.jpg'])).toBe(true);
+	});
+
+	it('returns false for disallowed extension', () => {
+		expect(validateFileExtension('script.exe', ['.png', '.jpg'])).toBe(false);
+	});
+
+	it('is case-insensitive', () => {
+		expect(validateFileExtension('photo.PNG', ['.png'])).toBe(true);
+	});
+});