fix: stabilize core error handling

Remove production panic and unwrap paths from core modules.

Propagate bookmark encryption failures, harden file watcher and temp mapped file handling, and clean up dead code in shared utilities.

src/ui/activities/auth/bookmarks.rs

@@ -71,7 +71,10 @@ impl AuthActivity {
         };
 
         if let Some(bookmarks_cli) = self.bookmarks_client_mut() {
-            bookmarks_cli.add_bookmark(name.clone(), params, save_password);
+            if let Err(err) = bookmarks_cli.add_bookmark(name.clone(), params, save_password) {
+                self.mount_error(format!("Could not save bookmark: {err}"));
+                return;
+            }
             // Save bookmarks
             self.write_bookmarks();
             // Remove `name` from bookmarks if exists
@@ -121,7 +124,10 @@ impl AuthActivity {
             }
         };
         if let Some(bookmarks_cli) = self.bookmarks_client_mut() {
-            bookmarks_cli.add_recent(params);
+            if let Err(err) = bookmarks_cli.add_recent(params) {
+                self.mount_error(format!("Could not save recent host: {err}"));
+                return;
+            }
             // Save bookmarks
             self.write_bookmarks();
         }