feat(ui): add scan progress and error reporting to UI (#4094)

* feat(scanner): add LastScanError tracking to scanner status

- Introduced LastScanErrorKey constant for error tracking.
- Updated StatusInfo struct to include LastError field.
- Modified scanner logic to store and retrieve last scan error.
- Enhanced ScanStatus response to include error information.
- Updated UI components to display last scan error when applicable.
- Added tests to verify last scan error functionality.

Signed-off-by: Deluan <deluan@navidrome.org>

* feat(scanner): enhance scan status with type and elapsed time tracking

- Added LastScanTypeKey and LastScanStartTimeKey constants for tracking scan type and start time.
- Updated StatusInfo struct to include ScanType and ElapsedTime fields.
- Implemented getScanInfo method to retrieve scan type, elapsed time, and last error.
- Modified scanner logic to store scan type and start time during scans.
- Enhanced ScanStatus response and UI components to display scan type and elapsed time.
- Added formatShortDuration utility for better elapsed time representation.
- Updated activity reducer to handle new scan status fields.

Signed-off-by: Deluan <deluan@navidrome.org>

* refactor(tests): consolidate controller status tests into a single file

- Removed the old controller_status_test.go file.
- Merged relevant tests into the new controller_test.go file for better organization and maintainability.
- Ensured all existing test cases for controller status are preserved and functional.

Signed-off-by: Deluan <deluan@navidrome.org>

* Fix formatting issues

* refactor(scanner): update getScanInfo method documentation

---------

Signed-off-by: Deluan <deluan@navidrome.org>

server/events/events.go

@@ -37,9 +37,12 @@ func (e *baseEvent) Data(evt Event) string {
 
 type ScanStatus struct {
 	baseEvent
-	Scanning    bool  `json:"scanning"`
-	Count       int64 `json:"count"`
-	FolderCount int64 `json:"folderCount"`
+	Scanning    bool          `json:"scanning"`
+	Count       int64         `json:"count"`
+	FolderCount int64         `json:"folderCount"`
+	Error       string        `json:"error"`
+	ScanType    string        `json:"scanType"`
+	ElapsedTime time.Duration `json:"elapsedTime"`
 }
 
 type KeepAlive struct {