Refactor workflow internals into package boundaries

[YunaBraska]

Summary

• keep the refactor-service-boundaries behavior, but restore the intended package map: entry, git, i18n, run, settings, state, syntax
• fold plugin entrypoints and IntelliJ wiring into short boundary classes instead of a flat services package
• move tests into matching package groups while keeping shared fake IDE/server helpers under test

Checks

• ./gradlew --no-daemon compileJava compileTestJava --warning-mode all
• ./gradlew --no-daemon test --warning-mode all
• ./gradlew --no-daemon check verifyPlugin buildPlugin --warning-mode all

Notes

• Plugin verifier reported all configured IDE targets as compatible.