fix: address all review findings (context timeout, docs, early exit)

- Overall context timeout now derived from LLM timeout + 1 minute
  (no longer hardcoded 3min that could conflict with longer LLM timeouts)
- Clarify concurrency docs: With* methods are setup-only, not concurrent
- Add ctx.Err() checks in fetchFileContext and fetchPatterns loops
  (break early on cancellation instead of making unnecessary requests)

cmd/review-bot/main.go

@@ -70,8 +70,9 @@ func main() {
 		llmClient.WithTimeout(time.Duration(*llmTimeout) * time.Second)
 	}
 
-	// Create a top-level context with a 3-minute timeout for all operations
-	ctx, cancel := context.WithTimeout(context.Background(), 3*time.Minute)
+	// Create a top-level context. Timeout derived from LLM timeout + 1 min for other ops.
+	overallTimeout := time.Duration(*llmTimeout)*time.Second + time.Minute
+	ctx, cancel := context.WithTimeout(context.Background(), overallTimeout)
 	defer cancel()
 
 	log.Printf("Reviewing PR #%d on %s/%s", prNumber, owner, repoName)
@@ -178,6 +179,9 @@ func main() {
 func fetchFileContext(ctx context.Context, client *gitea.Client, owner, repo, ref string, files []gitea.ChangedFile) string {
 	var sb strings.Builder
 	for _, f := range files {
+		if ctx.Err() != nil {
+			break
+		}
 		if f.Status == "removed" {
 			continue // Skip deleted files
 		}
@@ -205,6 +209,9 @@ func fetchPatterns(ctx context.Context, client *gitea.Client, patternsRepo, patt
 	paths := strings.Split(patternsFiles, ",")
 
 	for _, repoRef := range repos {
+		if ctx.Err() != nil {
+			break
+		}
 		repoRef = strings.TrimSpace(repoRef)
 		if repoRef == "" {
 			continue

llm/client.go

@@ -13,6 +13,7 @@ import (
 
 // Client calls an OpenAI-compatible chat completion API.
 // A Client is safe for concurrent use by multiple goroutines after construction.
+// WithTimeout and WithTemperature must be called during setup, before concurrent use.
 type Client struct {
 	baseURL     string
 	apiKey      string