feat(coding-agent): add user_bash event and theme API extensions

- user_bash event for intercepting ! and !! commands (#528)
- Extensions can return { operations } or { result } to redirect/replace
- executeBashWithOperations() for custom BashOperations execution
- session.recordBashResult() for extensions handling bash themselves
- Theme API: getAllThemes(), getTheme(), setTheme() on ctx.ui
- mac-system-theme.ts example: sync with macOS dark/light mode
- Updated ssh.ts to use user_bash event

packages/coding-agent/examples/extensions/mac-system-theme.ts

@@ -0,0 +1,25 @@
+/**
+ * Syncs pi theme with macOS system appearance (dark/light mode).
+ *
+ * Usage:
+ *   pi -e examples/extensions/mac-system-theme.ts
+ */
+
+import { execSync } from "node:child_process";
+import type { ExtensionAPI } from "@mariozechner/pi-coding-agent";
+
+function isDarkMode(): boolean {
+	try {
+		execSync("defaults read -g AppleInterfaceStyle", { encoding: "utf-8" });
+		return true; // Returns "Dark" if dark mode
+	} catch {
+		return false; // Throws if light mode
+	}
+}
+
+export default function (pi: ExtensionAPI) {
+	pi.on("session_start", (_event, ctx) => {
+		const theme = isDarkMode() ? "dark" : "light";
+		ctx.ui.setTheme(theme);
+	});
+}

packages/coding-agent/examples/extensions/ssh.ts

@@ -199,6 +199,13 @@ export default function (pi: ExtensionAPI) {
 		}
 	});
 
+	// Handle user ! commands via SSH
+	pi.on("user_bash", (_event) => {
+		const ssh = getSsh();
+		if (!ssh) return; // No SSH, use local execution
+		return { operations: createRemoteBashOps(ssh.remote, ssh.remoteCwd, localCwd) };
+	});
+
 	// Replace local cwd with remote cwd in system prompt
 	pi.on("before_agent_start", async (event) => {
 		const ssh = getSsh();