feat: add provider contexts and application enhancers

[ZhiXiao-Lin]

Summary

• add context-scoped provider identities, caches, references, and resolution semantics
• add application-level enhancer registration, ordering, retries, lazy-module behavior, and topology handling
• extend controller/message handler contexts, transport patterns, pipeline interception, and WebSocket integration
• document the completed roadmap and add broad integration/regression coverage

Validation

• cargo fmt --all
• cargo test --all-targets --no-default-features
• cargo test --all-targets
• cargo clippy --all-targets --no-default-features -- -D warnings
• cargo clippy --all-targets -- -D warnings
• git diff --check