fix: update tests for InstalledSkill new fields and missing hook mocks

- Add content_hash and updated_at fields to 4 InstalledSkill literals in skill_sync.rs
- Add useCheckSkillUpdates and useUpdateSkill to UnifiedSkillsPanel test mock
- Suppress unused import warning in auto_launch.rs test module

src-tauri/tests/skill_sync.rs

@@ -110,6 +110,8 @@ fn sync_to_app_removes_disabled_and_orphaned_ssot_symlinks() {
                 opencode: false,
             },
             installed_at: 0,
+            content_hash: None,
+            updated_at: 0,
         })
         .expect("save disabled skill");
 
@@ -154,6 +156,8 @@ fn uninstall_skill_creates_backup_before_removing_ssot() {
                 opencode: false,
             },
             installed_at: 123,
+            content_hash: None,
+            updated_at: 0,
         })
         .expect("save skill");
 
@@ -222,6 +226,8 @@ fn restore_skill_backup_restores_files_to_ssot_and_current_app() {
                 opencode: false,
             },
             installed_at: 456,
+            content_hash: None,
+            updated_at: 0,
         })
         .expect("save skill");
 
@@ -303,6 +309,8 @@ fn delete_skill_backup_removes_backup_directory() {
                 opencode: false,
             },
             installed_at: 789,
+            content_hash: None,
+            updated_at: 0,
         })
         .expect("save skill");