refactor(media): consolidate upload/edit/download into MediaService

Merge UploadService, EditService, JobOrchestrationService, and
DownloadService into a single MediaService with a unified Job lifecycle
(READY → PROCESSING → SUCCEEDED/FAILED via JobState enum).

- Add MediaController (/api/v1/media) exposing compress, save, and clip
- Add JobController (/api/v1/job) for status polling and file download
- Move clip/thumbnail download into ClipController (/{id}/media, /{id}/thumbnail)
- Move stream saveSection/clip from StreamService into MediaService
- Simplify Job DTO: remove dual ClipOptions/files, add ProgressTracker and download file
- Refactor JobRegistryService.add() → generateJob() to co-locate creation and registration
- Wire FFmpeg out_time_ms progress parsing into StreamActionsService via CommandRunner
- Rename GET /api/v1/auth/user → GET /api/v1/user/me
- Delete DownloadController, MetadataController, UploadController

src/main/java/com/ddf/vodsystem/controllers/UserController.java

@@ -14,7 +14,7 @@ import org.springframework.web.bind.annotation.*;
 import java.util.Optional;
 
 @RestController
-@RequestMapping("/api/v1/auth/")
+@RequestMapping("/api/v1/user/")
 public class UserController {
     private final UserService userService;
 
@@ -25,7 +25,7 @@ public class UserController {
         this.userService = userService;
     }
 
-    @GetMapping("/user")
+    @GetMapping("/me")
     public ResponseEntity<APIResponse<User>> user() {
         Optional<User> user = userService.getLoggedInUser();