[AZ-178] Fix Critical/High security findings: auth, CVEs, non-root containers, per-job SSE

- Pin all deps; h11==0.16.0 (CVE-2025-43859), python-multipart>=1.3.1 (CVE-2026-28356), PyJWT==2.12.1
- Add HMAC JWT verification (require_auth FastAPI dependency, JWT_SECRET-gated)
- Fix TokenManager._refresh() to use ADMIN_API_URL instead of ANNOTATIONS_URL
- Rename POST /detect → POST /detect/image (image-only, rejects video files)
- Replace global SSE stream with per-job SSE: GET /detect/{media_id} with event replay buffer
- Apply require_auth to all 4 protected endpoints
- Fix on_annotation/on_status closure to use mutable current_id for correct post-upload event routing
- Add non-root appuser to Dockerfile and Dockerfile.gpu
- Add JWT_SECRET to e2e/docker-compose.test.yml and run-tests.sh
- Update all e2e tests and unit tests for new endpoints and HMAC token signing
- 64/64 tests pass

Made-with: Cursor

e2e/docker-compose.test.yml

@@ -25,6 +25,7 @@ services:
     environment:
       LOADER_URL: http://mock-loader:8080
       ANNOTATIONS_URL: http://mock-annotations:8081
+      JWT_SECRET: test-secret-e2e-only
     volumes:
       - ./fixtures/classes.json:/app/classes.json
       - ./fixtures:/media
@@ -47,6 +48,7 @@ services:
     environment:
       LOADER_URL: http://mock-loader:8080
       ANNOTATIONS_URL: http://mock-annotations:8081
+      JWT_SECRET: test-secret-e2e-only
     volumes:
       - ./fixtures/classes.json:/app/classes.json
       - ./fixtures:/media
@@ -64,6 +66,8 @@ services:
     depends_on:
       - mock-loader
       - mock-annotations
+    environment:
+      JWT_SECRET: test-secret-e2e-only
     volumes:
       - ./fixtures:/media
       - ./results:/results