Flutter url_launcher Engineering

Mission

Treat url_launcher as a platform handoff API, not a browser framework or proof that an external business action completed. Use this loop:

identify external action
→ decide whether url_launcher is appropriate
→ classify destination trust
→ construct a safe Uri
→ choose an intentional LaunchMode
→ query capability only if it changes UX
→ launch once
→ handle false/exception with fallback
→ verify downstream business completion separately
→ test platform-specific behavior