fix(locations): canonicalize paths and register watcher on location add

Two upstream bugs fixed:

1. LocationManager::add_location() stored paths as-is without
   canonicalization. Relative paths (e.g. from cwd-dependent contexts)
   broke the watcher, volume manager, and indexer pipelines.
   Now calls tokio::fs::canonicalize() on local physical paths before
   storing, with UNC prefix stripping on Windows.

2. LocationAddAction::execute() never registered new locations with the
   FsWatcherService. The watcher only discovered locations at startup
   via load_library_locations(). Any location added at runtime had no
   filesystem monitoring — creates, deletes, and renames went undetected.
   Now calls fs_watcher.watch_location() after successful creation.

core/src/location/manager.rs

@@ -46,6 +46,40 @@ impl LocationManager {
 		job_policies: Option<String>,
 		volume_manager: &crate::volume::VolumeManager,
 	) -> LocationResult<(Uuid, String)> {
+		// Canonicalize local physical paths to absolute form before storing.
+		// Relative paths break the watcher, volume resolution, and indexer.
+		// Only for local device — remote paths can't be resolved locally.
+		let sd_path = if sd_path.is_local() {
+			if let crate::domain::addressing::SdPath::Physical { device_slug, path } = sd_path {
+				let canonical = tokio::fs::canonicalize(&path).await.map_err(|e| {
+					LocationError::InvalidPath(format!(
+						"Failed to resolve path {}: {}",
+						path.display(),
+						e
+					))
+				})?;
+				// On Windows, canonicalize() returns UNC paths (\\?\C:\...) which break
+				// starts_with() matching throughout the codebase. Strip the prefix.
+				#[cfg(windows)]
+				let canonical = {
+					let s = canonical.to_string_lossy();
+					if let Some(stripped) = s.strip_prefix(r"\\?\") {
+						std::path::PathBuf::from(stripped)
+					} else {
+						canonical
+					}
+				};
+				crate::domain::addressing::SdPath::Physical {
+					device_slug,
+					path: canonical,
+				}
+			} else {
+				sd_path
+			}
+		} else {
+			sd_path
+		};
+
 		info!("Adding location: {}", sd_path);
 
 		// Validate the path based on type

core/src/ops/locations/add/action.rs

@@ -102,6 +102,31 @@ impl LibraryAction for LocationAddAction {
 			.await
 			.map_err(|e| ActionError::Internal(e.to_string()))?;
 
+		// Register the new location with the filesystem watcher so changes
+		// (creates, deletes, renames) are detected in real-time.
+		// Without this, the watcher only learns about locations at startup.
+		if let Some(local_path) = self.input.path.as_local_path() {
+			if let Some(fs_watcher) = context.get_fs_watcher().await {
+				use crate::ops::indexing::handlers::LocationMeta;
+				use crate::ops::indexing::RuleToggles;
+
+				// Use canonical path to match what add_location stored in DB
+				let root_path = tokio::fs::canonicalize(local_path)
+					.await
+					.unwrap_or_else(|_| local_path.to_path_buf());
+
+				let meta = LocationMeta {
+					id: location_id,
+					library_id: library.id(),
+					root_path,
+					rule_toggles: RuleToggles::default(),
+				};
+				if let Err(e) = fs_watcher.watch_location(meta).await {
+					tracing::warn!("Failed to register location with watcher: {}", e);
+				}
+			}
+		}
+
 		// Parse the job ID from the string returned by add_location
 		let job_id = if !job_id_string.is_empty() {
 			Some(