feat: add context.Context + unexport client fields

REVIEW.md findings 1-4, 14:
- All Gitea client methods now accept context.Context as first param
- All LLM client methods now accept context.Context as first param
- Use http.NewRequestWithContext for cancellation/timeout support
- Main uses 3-minute timeout context for all operations
- Unexport Client struct fields (baseURL, token, apiKey, etc.)
- Use bytes.NewReader instead of strings.NewReader(string(...))

integration_test.go

@@ -3,6 +3,7 @@
 package main
 
 import (
+	"context"
 	"os"
 	"strconv"
 	"testing"
@@ -44,7 +45,7 @@ func TestIntegration_FullReviewFlow(t *testing.T) {
 	// Parse owner/repo
 	owner, repoName := "", ""
 	for i, c := range giteaRepo {
-		if c == / {
+		if c == '/' {
 			owner = giteaRepo[:i]
 			repoName = giteaRepo[i+1:]
 			break
@@ -54,16 +55,18 @@ func TestIntegration_FullReviewFlow(t *testing.T) {
 		t.Fatalf("Invalid repo format %q", giteaRepo)
 	}
 
+	ctx := context.Background()
+
 	// Step 1: Fetch PR
 	giteaClient := gitea.NewClient(giteaURL, giteaToken)
-	pr, err := giteaClient.GetPullRequest(owner, repoName, prNumber)
+	pr, err := giteaClient.GetPullRequest(ctx, owner, repoName, prNumber)
 	if err != nil {
 		t.Fatalf("GetPullRequest: %v", err)
 	}
 	t.Logf("PR: %s (sha: %s)", pr.Title, pr.Head.Sha)
 
 	// Step 2: Fetch diff
-	diff, err := giteaClient.GetPullRequestDiff(owner, repoName, prNumber)
+	diff, err := giteaClient.GetPullRequestDiff(ctx, owner, repoName, prNumber)
 	if err != nil {
 		t.Fatalf("GetPullRequestDiff: %v", err)
 	}
@@ -78,7 +81,7 @@ func TestIntegration_FullReviewFlow(t *testing.T) {
 
 	// Step 4: Call LLM
 	llmClient := llm.NewClient(llmBaseURL, llmAPIKey, llmModel)
-	response, err := llmClient.Complete([]llm.Message{
+	response, err := llmClient.Complete(ctx, []llm.Message{
 		{Role: "system", Content: systemPrompt},
 		{Role: "user", Content: userPrompt},
 	})