feat(worker): sharp pipeline with orientation, variants, exif strip

Task 20: services/worker package (@photo/worker, commonjs) with jest
unit/e2e configs mirroring api conventions (root .env via test/load-env.ts,
moduleNameMapper to @photo/contracts/db-cn/storage TS sources, maxWorkers 1,
test/reset.ts = MySQL TRUNCATE + MinIO photo-live/dev prefix wipe) and the
sharp processing pipeline runPipeline(): metadata whitelist gate
(jpeg/png/webp/avif/heif/tiff, else PipelineError UNSUPPORTED_TYPE),
decode failures mapped to PipelineError DECODE_FAILED, no-arg .rotate()
auto-orientation (EXIF 5-8 swaps stored width/height), thumb <=480w q75
and browse <=1920 q82 JPEG variants with withoutEnlargement, and no
withMetadata so outputs carry no EXIF/GPS at all. sharp 0.35 prebuilt
loads script-free under pnpm 10; its win32 libvips lacks a HEVC encoder,
so the HEVC-HEIF unit case self-skips with a console note (G2 verifies
with real iPhone samples) while the AV1-HEIF case covers the same
libheif decode path / 'heif' format bucket.

Co-Authored-By: Claude Code <noreply@anthropic.com>

services/worker/test/load-env.ts

@@ -0,0 +1,7 @@
+// services/worker/test/load-env.ts
+// 全仓库唯一 env 加载机制（Jest 侧）：仓库根 .env（与 services/api 同约定）。
+// 开发/生产经根 dotenv-cli 注入；运行时代码只读 process.env。
+import { join } from 'node:path';
+import { config } from 'dotenv';
+
+config({ path: join(__dirname, '../../../.env') });