Make skill loading filesystem-aware (#17720)

Migrates skill loading to support reading repo skills from the remote
environment.

codex-rs/core/src/thread_manager.rs

@@ -365,6 +365,10 @@ impl ThreadManager {
         self.state.mcp_manager.clone()
     }
 
+    pub fn environment_manager(&self) -> Arc<EnvironmentManager> {
+        self.state.environment_manager.clone()
+    }
+
     pub fn get_models_manager(&self) -> Arc<ModelsManager> {
         self.state.models_manager.clone()
     }
@@ -903,14 +907,24 @@ impl ThreadManagerState {
         parent_trace: Option<W3cTraceContext>,
         user_shell_override: Option<crate::shell::Shell>,
     ) -> CodexResult<NewThread> {
-        let watch_registration = self
-            .skills_watcher
-            .register_config(
-                &config,
-                self.skills_manager.as_ref(),
-                self.plugins_manager.as_ref(),
-            )
-            .await;
+        let environment = self
+            .environment_manager
+            .current()
+            .await
+            .map_err(|err| CodexErr::Fatal(format!("failed to create environment: {err}")))?;
+        let watch_registration = match environment.as_ref() {
+            Some(environment) if !environment.is_remote() => {
+                self.skills_watcher
+                    .register_config(
+                        &config,
+                        self.skills_manager.as_ref(),
+                        self.plugins_manager.as_ref(),
+                        Some(environment.get_filesystem()),
+                    )
+                    .await
+            }
+            Some(_) | None => crate::file_watcher::WatchRegistration::default(),
+        };
         let CodexSpawnOk {
             codex, thread_id, ..
         } = Codex::spawn(CodexSpawnArgs {