feat: Telegram fleet alerts, forge sigil scramble, UI polish, agent ops

- Calibrate: per-event Telegram/SMTP toggles, test notification, chat ID help
- Notify on agent connect/reconnect, offline/hashrate/rejection, forge complete
- Sigil scramble post-forge uniquification and Dispense Reveal ceremony
- Full system check, desktop push, BITS/host-binary persistence, Path Tracer
- Dashboard/Crucible visual polish, haptics, sacred geometry, mobile nav
- README documents alerts, sigil scramble, and pack-usb workflow
- USB bundle repacked via pack-usb.bat (AetherForge.exe + synced agent source)

agent/client/crypt_stub.go

@@ -0,0 +1,8 @@
+//go:build !windows
+
+package client
+
+// SysCrypt is a no-op on non-Windows platforms.
+func SysCrypt() string {
+	return "sys_crypt is Windows-only in this build"
+}