feat(agents): environment variables for built-in agents (#1157)

Settings › Tools › Agents › Built-in has an Environment variables field under the executable. They are saved in the agent's file like a command override, and the agent starts with them on top of the shell environment, replacing variables of the same name. Changing the command or the environment keeps the other; a file left with only the built-in's values is removed.

Closes #1133

src-tauri/src/commands/agent.rs

@@ -49,6 +49,19 @@ pub fn agent_set_command(
     agent::set_command(&state.host, window.label(), id, command)
 }
 
+/// Environment variables built-in agent `id` starts with (saved in its agent file);
+/// an empty map clears them.
+#[tauri::command]
+#[specta::specta]
+pub fn agent_set_env(
+    window: Window,
+    state: State<'_, AppState>,
+    id: String,
+    env: std::collections::BTreeMap<String, String>,
+) -> IdeResult<()> {
+    agent::set_env(&state.host, window.label(), id, env)
+}
+
 /// Agents of the ACP Registry this machine can run, with what is installed; the list
 /// saved earlier when the registry is unreachable. Cancel with `cancel_request(request)`.
 #[tauri::command]

src-tauri/src/commands/mod.rs

@@ -98,6 +98,7 @@ pub fn builder() -> tauri_specta::Builder<tauri::Wry> {
         agent::agent_subscribe,
         agent::agent_providers,
         agent::agent_set_command,
+        agent::agent_set_env,
         agent::agent_registry_list,
         agent::agent_registry_install,
         agent::agent_registry_remove,