Complete Task 3.3: ProgressService already uses key identifier

- Verified ProgressService correctly uses 'key' as primary series identifier
- ProgressUpdate dataclass has key/folder fields with proper docstrings
- All methods accept and handle key/folder parameters
- to_dict() properly serializes key/folder when present
- 25 unit tests pass including key/folder tests
- Infrastructure documentation already up to date
- Removed completed task details from instructions.md

instructions.md

@@ -171,37 +171,7 @@ For each task completed:
 
 ### Phase 3: Service Layer
 
-✅ **Tasks 3.1 and 3.2 completed and committed to git (November 2025)**
+✅ **Tasks 3.1, 3.2, and 3.3 completed and committed to git (November 2025)**
-
----
-
-#### Task 3.3: Update ProgressService to Use Key
-
-**File:** [`src/server/services/progress_service.py`](src/server/services/progress_service.py)
-
-**Objective:** Ensure `ProgressService` uses `key` for all progress tracking.
-
-**Steps:**
-
-1. Open [`src/server/services/progress_service.py`](src/server/services/progress_service.py)
-2. Review all methods that handle progress events
-3. Ensure progress events include `key` as identifier
-4. Update any internal tracking to use `key` instead of `folder`
-5. Update event payloads to include both `key` and `folder` where needed
-6. Update docstrings to clarify identifier usage
-
-**Success Criteria:**
-
--   [ ] All progress events include `key`
--   [ ] Internal tracking uses `key`
--   [ ] Event payloads structured correctly
--   [ ] All progress service tests pass
-
-**Test Command:**
-
-```bash
-conda run -n AniWorld python -m pytest tests/unit/ -k "ProgressService" -v
-```
 
 ---