feat: Phase 4 — LLM 集成，PR 描述生成与 AI 代码审查

go.mod

@@ -4,7 +4,9 @@ go 1.25.0
 
 require (
 	github.com/gin-gonic/gin v1.10.0
+	github.com/go-git/go-git/v5 v5.19.1
 	github.com/mattn/go-sqlite3 v1.14.24
+	github.com/sashabaranov/go-openai v1.41.2
 )
 
 require (
@@ -22,7 +24,6 @@ require (
 	github.com/gin-contrib/sse v0.1.0 // indirect
 	github.com/go-git/gcfg v1.5.1-0.20230307220236-3a3c6141e376 // indirect
 	github.com/go-git/go-billy/v5 v5.9.0 // indirect
-	github.com/go-git/go-git/v5 v5.19.1 // indirect
 	github.com/go-playground/locales v0.14.1 // indirect
 	github.com/go-playground/universal-translator v0.18.1 // indirect
 	github.com/go-playground/validator/v10 v10.20.0 // indirect