Résumé Studio v0.1.0

Fix broken macOS code signature and add real README

Tauri only ad-hoc-signed the raw executable, not the full .app bundle,
so Gatekeeper rejected it as "damaged" (no resource seal) regardless of
notarization status. Setting bundle.macOS.signingIdentity fixes this at
the config level so every future build is properly sealed.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>