Add native Unicode text input

[enaboapps]

Summary

• add a native Windows text input helper that sends Unicode text with SendInput
• route complex keyboard.typeText input through the helper before falling back to clipboard paste
• harden clipboard fallback with write verification, retry, and restoration of the previous clipboard value
• package, sign, verify, and smoke-check the new helper alongside existing native helpers

Closes #208

Verification

• npm test -- src/main/input/text-inserter.test.ts src/main/input/text-input-helper-client.test.ts src/main/input/command-executor.test.ts
• npm run typecheck
• npm test
• npm run build
• npm run native:build
• npm run native:smoke-text