[Sync] adopt unified stow layout from the private repo

Mirrors the private dots tree at 900bdda: one shared base plus per-host
overlays, replacing the old flat .config/ layout (last synced 2026-06-28).

- packages: common/ gui/ wm/ lw/ fl/ + install.sh and bin/ tooling (dotsync,
  reconcile-hyde.sh)
- new README (layout, deploy order, HyDE dependency), plus ToDo.md and
  HYDE-UPDATE.md
- current HyDE waybar rig (layouts/, cava), pi agent extensions, claude/
  config, tmux, presenterm, aichat roles
- drops stale duplicates and generated cruft that should never have been
  tracked: the second top-level .pi/ copy, btop.log, zellij config.kdl.bak,
  fish_variables, nvim codecompanion.lua
- .pi/agent/auth.json is gitignored now; auth.json.example ships instead
- fl/ and wm/ hypr themes/ stay untracked (HyDE-generated per machine, per
  the root .gitignore)

common/.pi/agent/extensions/notify.ts

@@ -0,0 +1,55 @@
+/**
+ * Pi Notify Extension
+ *
+ * Sends a native terminal notification when Pi agent is done and waiting for input.
+ * Supports multiple terminal protocols:
+ * - OSC 777: Ghostty, iTerm2, WezTerm, rxvt-unicode
+ * - OSC 99: Kitty
+ * - Windows toast: Windows Terminal (WSL)
+ */
+
+import type { ExtensionAPI } from "@earendil-works/pi-coding-agent";
+
+function windowsToastScript(title: string, body: string): string {
+	const type = "Windows.UI.Notifications";
+	const mgr = `[${type}.ToastNotificationManager, ${type}, ContentType = WindowsRuntime]`;
+	const template = `[${type}.ToastTemplateType]::ToastText01`;
+	const toast = `[${type}.ToastNotification]::new($xml)`;
+	return [
+		`${mgr} > $null`,
+		`$xml = [${type}.ToastNotificationManager]::GetTemplateContent(${template})`,
+		`$xml.GetElementsByTagName('text')[0].AppendChild($xml.CreateTextNode('${body}')) > $null`,
+		`[${type}.ToastNotificationManager]::CreateToastNotifier('${title}').Show(${toast})`,
+	].join("; ");
+}
+
+function notifyOSC777(title: string, body: string): void {
+	process.stdout.write(`\x1b]777;notify;${title};${body}\x07`);
+}
+
+function notifyOSC99(title: string, body: string): void {
+	// Kitty OSC 99: i=notification id, d=0 means not done yet, p=body for second part
+	process.stdout.write(`\x1b]99;i=1:d=0;${title}\x1b\\`);
+	process.stdout.write(`\x1b]99;i=1:p=body;${body}\x1b\\`);
+}
+
+function notifyWindows(title: string, body: string): void {
+	const { execFile } = require("child_process");
+	execFile("powershell.exe", ["-NoProfile", "-Command", windowsToastScript(title, body)]);
+}
+
+function notify(title: string, body: string): void {
+	if (process.env.WT_SESSION) {
+		notifyWindows(title, body);
+	} else if (process.env.KITTY_WINDOW_ID) {
+		notifyOSC99(title, body);
+	} else {
+		notifyOSC777(title, body);
+	}
+}
+
+export default function (pi: ExtensionAPI) {
+	pi.on("agent_end", async () => {
+		notify("Pi", "Ready for input");
+	});
+}