Fix Signboard 1.7.2 packaging and add launch gate

[cdevroe]

Summary

• include the packaged bin/** and shared/** runtime source roots
• bump Signboard to 1.7.2
• make every macOS distribution build launch its own packaged app with isolated user data
• validate required packaging globs during release verification
• repair the unsigned local macOS build helper

Verification

• signed universal app launch test passed
• Developer ID signature verified
• Apple notarization and staple validation passed
• Gatekeeper assessment passed
• packaged CLI launched from app.asar/bin/signboard.js
• 79 Playwright Electron tests passed
• updater, app-settings, local-date, CLI-install, desktop-CLI, packaging, and release-artifact tests passed