Hermes Tailscale 0.0.3

Hermes Tailscale 0.0.3 Security hardening from issue #1. - xterm is verified against a pinned SHA-384 before it runs. esm.sh dropped. A local xterm.js next to plugin.js is used first when present. - Serve port is editable and checked for a listener before tailscale serve runs. - status-cache.json is created 0600 on macOS and Linux and deleted when the plugin unloads. - node:test suite for shell quoting and CLI parsing, run in CI on Ubuntu and Windows. - MIT license, version in the plugin manifest, compatibility table. Tested against: Hermes Desktop on Windows 11, Tailscale 1.102.