Add ctx.ui.theme getter for styling status text with theme colors

- Add theme property to HookUIContext interface
- Implement in interactive, RPC, and no-op contexts
- Add status-line.ts example hook
- Document styling with theme colors in hooks.md

packages/coding-agent/examples/hooks/README.md

@@ -26,6 +26,7 @@ cp permission-gate.ts ~/.pi/agent/hooks/
 | `custom-compaction.ts` | Custom compaction that summarizes entire conversation |
 | `qna.ts` | Extracts questions from last response into editor via `ctx.ui.setEditorText()` |
 | `snake.ts` | Snake game with custom UI, keyboard handling, and session persistence |
+| `status-line.ts` | Shows turn progress in footer via `ctx.ui.setStatus()` with themed colors |
 
 ## Writing Hooks
 

packages/coding-agent/examples/hooks/status-line.ts

@@ -0,0 +1,38 @@
+/**
+ * Status Line Hook
+ *
+ * Demonstrates ctx.ui.setStatus() for displaying persistent status text in the footer.
+ * Shows turn progress with themed colors.
+ */
+
+import type { HookAPI } from "@mariozechner/pi-coding-agent";
+
+export default function (pi: HookAPI) {
+	let turnCount = 0;
+
+	pi.on("session_start", async (_event, ctx) => {
+		const theme = ctx.ui.theme;
+		ctx.ui.setStatus("status-demo", theme.fg("dim", "Ready"));
+	});
+
+	pi.on("turn_start", async (_event, ctx) => {
+		turnCount++;
+		const theme = ctx.ui.theme;
+		const spinner = theme.fg("accent", "●");
+		const text = theme.fg("dim", ` Turn ${turnCount}...`);
+		ctx.ui.setStatus("status-demo", spinner + text);
+	});
+
+	pi.on("turn_end", async (_event, ctx) => {
+		const theme = ctx.ui.theme;
+		const check = theme.fg("success", "✓");
+		const text = theme.fg("dim", ` Turn ${turnCount} complete`);
+		ctx.ui.setStatus("status-demo", check + text);
+	});
+
+	pi.on("session_new", async (_event, ctx) => {
+		turnCount = 0;
+		const theme = ctx.ui.theme;
+		ctx.ui.setStatus("status-demo", theme.fg("dim", "Ready"));
+	});
+}