Fix remote skill popup loading (#17702)

## Summary

Fix the TUI `$` skill popup so personal skills appear reliably when
Codex is connected to a remote app-server.

## What changed

- load skills on TUI startup with an explicit forced refresh
- refresh skills using the actual current cwd instead of an empty `cwds`
list
- resync an already-open `$` popup when skill mentions are updated
- add a regression test for refreshing an open mention popup

## Root cause

The TUI was sometimes sending `list_skills` with `cwds: []` after
`SessionConfigured`.

For the launchd app-server flow, the server resolved that empty cwd list
to its own process cwd, which was `/`. The response therefore came back
tagged with `cwd: "/"`, and the TUI later filtered skills by exact cwd
match against the actual project cwd such as `/Users/starr/code/dream`.
That dropped all personal skills from the mention list, so `$` only
showed plugins/apps.

## Verification

Built successfully with remote cache disabled:

```bash
cd /Users/starr/code/codex-worktrees/starr-skill-popup-20260413130509
bazel --output_base=/tmp/codex-bazel-verify-starr-skill-popup build //codex-rs/cli:codex --noremote_accept_cached --noremote_upload_local_results --disk_cache=
```

Also verified interactively in a PTY against the live app-server at
`ws://127.0.0.1:4511`:
- launched the built TUI
- typed `$`
- confirmed personal skills appeared in the popup, including entries
such as `Applied Devbox`, `CI Debug`, `Channel Summarization`, `Codex PR
Review`, and `Daily Digest`

## Files changed

- `codex-rs/tui/src/app.rs`
- `codex-rs/tui/src/chatwidget.rs`
- `codex-rs/tui/src/bottom_pane/chat_composer.rs`

Co-authored-by: Codex <noreply@openai.com>

codex-rs/tui/src/bottom_pane/chat_composer.rs

@@ -522,6 +522,7 @@ impl ChatComposer {
 
     pub fn set_skill_mentions(&mut self, skills: Option<Vec<SkillMetadata>>) {
         self.skills = skills;
+        self.sync_popups();
     }
 
     pub fn set_plugin_mentions(&mut self, plugins: Option<Vec<PluginCapabilitySummary>>) {
@@ -5053,6 +5054,42 @@ mod tests {
         assert_eq!(mention.path, Some("plugin://sample@test".to_string()));
     }
 
+    #[test]
+    fn set_skill_mentions_refreshes_open_mention_popup() {
+        let (tx, _rx) = unbounded_channel::<AppEvent>();
+        let sender = AppEventSender::new(tx);
+        let mut composer = ChatComposer::new(
+            /*has_input_focus*/ true,
+            sender,
+            /*enhanced_keys_supported*/ false,
+            "Ask Codex to do anything".to_string(),
+            /*disable_paste_burst*/ false,
+        );
+        composer.set_text_content("$".to_string(), Vec::new(), Vec::new());
+        assert!(matches!(composer.active_popup, ActivePopup::None));
+
+        let skill_path = test_path_buf("/tmp/skill/SKILL.md").abs();
+        composer.set_skill_mentions(Some(vec![SkillMetadata {
+            name: "codex".to_string(),
+            description: "Primary personal Codex repo skill.".to_string(),
+            short_description: None,
+            interface: None,
+            dependencies: None,
+            policy: None,
+            path_to_skills_md: skill_path.clone(),
+            scope: codex_protocol::protocol::SkillScope::User,
+        }]));
+
+        let ActivePopup::Skill(popup) = &composer.active_popup else {
+            panic!("expected mention popup to open after skills update");
+        };
+        let mention = popup
+            .selected_mention()
+            .expect("expected skill mention to be selected");
+        assert_eq!(mention.insert_text, "$codex".to_string());
+        assert_eq!(mention.path, Some(skill_path.display().to_string()));
+    }
+
     #[test]
     fn mention_items_show_plugin_owned_skill_and_app_duplicates() {
         let skill_path = test_path_buf("/tmp/repo/google-calendar/SKILL.md").abs();