v0.3.2 — Reliable desktop plugin startup

Codex desktop could report OpenPencil as installed while its MCP server failed to start because the desktop PATH could not find the terminal's Node executable. The plugin now launches with the Node executable registered privately by setup, with Node 22+ validation and local fallbacks. System PATH, existing Node installations and unrelated MCP servers are preserved.

Setup now verifies the installed plugin through Codex's actual app-server loader before reporting success, including the expected plugin identity and canvas tools. Run npm run host-check to diagnose loading without creating a chat or editing a design.

Validation:

• 69 tests and package checks pass; the Node 22/24 matrix passes on macOS, Windows and Linux.
• Fresh installation passes on all six OS/CPU builds, including host loading, native edit/save/reopen, terminal PNG/save and repeat setup.
• The bundled desktop app-server reproduced the previous failure and now loads the installed canvas controls.

After updating, reconnect the plugin or start a new chat to refresh its tools. A fresh host check does not prove an existing chat has reloaded. Embedded Codex presentation and actual canvas shortcut message delivery remain unverified.