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/StreamController.java

@@ -1,9 +1,7 @@
 package com.ddf.vodsystem.controllers;
 
-import com.ddf.vodsystem.controllers.dto.ClipSectionRequest;
 import com.ddf.vodsystem.controllers.dto.StreamResponse;
 import com.ddf.vodsystem.dto.APIResponse;
-import com.ddf.vodsystem.controllers.dto.SaveSectionRequest;
 import com.ddf.vodsystem.entities.Stream;
 import com.ddf.vodsystem.services.StreamService;
 import org.slf4j.Logger;
@@ -11,7 +9,6 @@ import org.slf4j.LoggerFactory;
 import org.springframework.http.ResponseEntity;
 import org.springframework.web.bind.annotation.*;
 
-import java.io.IOException;
 import java.util.List;
 import java.util.Optional;
 
@@ -49,20 +46,6 @@ public class StreamController {
         return ResponseEntity.ok(new APIResponse<>("success", "Heartbeat recorded", null));
     }
 
-    @PostMapping("/save")
-    public ResponseEntity<APIResponse<Void>> saveSection(
-            @RequestBody SaveSectionRequest request) throws IOException, InterruptedException {
-        streamService.saveSection(request.startTime(), request.endTime());
-        return ResponseEntity.accepted().body(new APIResponse<>("success", "Section saved", null));
-    }
-
-    @PostMapping("/clip")
-    public ResponseEntity<APIResponse<Void>> saveClip(
-            @RequestBody ClipSectionRequest request) throws IOException, InterruptedException {
-        streamService.clip(request.duration());
-        return ResponseEntity.accepted().body(new APIResponse<>("success", "Clip saved", null));
-    }
-
     @GetMapping("/history/{userId}")
     public ResponseEntity<APIResponse<List<Stream>>> getStreamHistory(@PathVariable Long userId) {
         List<Stream> history = streamService.getStreamHistory(userId);