Generate typed messages and detect dead keys by default

[gregjotau]

Summary

• generate typed message factories and validation references by default
• fail on unused messages and fragments by default
• treat generation as API creation, never as message usage
• link template usage with compiled factory calls and annotation reference tokens across all production modules in the Gradle build
• group modules that compile the same shared catalog and check it once
• keep explicit opt-outs for migration and external open-world catalogs
• prepare the breaking-default release as 0.8.0

Validation

• ./gradlew clean build
• focused tests for generated factories, dead factory detection, and inlined annotation references
• ReAI: detected 93 dead keys across 7,893 messages; passes after removing them from both locales
• Eteo: 388 messages, zero dead keys
• Ecomtools: 42 messages, zero dead keys
• Utin: no catalog, clean check