[codex] Add fsl-domain functional DDD and effect dialect

[rizumita]

Summary

• add the fsl-domain / fsl-effect dialect with aggregate decide/evolve lowering, async effect lifecycle checks, saga/process-manager support, and runtime replay
• add domain code generation for TypeScript plus simple Python/Kotlin/Swift/Rust scaffolds, domain testgen, schema, examples, and proposal/design docs
• update language docs, skill reference, bilingual intro pages, nav, changelog, and corpus snapshots

Validation

• pytest -q: 1023 passed, 78 skipped
• pytest tests/test_domain_dialect.py tests/test_db_dialect.py tests/test_ai_hard_contract.py tests/test_corpus_snapshot.py -q: 226 passed, 1 skipped
• pytest tests/test_domain_dialect.py -q: 15 passed
• python -m py_compile for changed Python modules
• git diff --check