Add unit tests, integration test, CI workflow, and conventions

- gitea/client_test.go: mock HTTP tests for all API methods + error cases
- llm/client_test.go: mock tests for completion, errors, timeouts
- review/parser_test.go: JSON parsing, markdown fences, validation
- review/formatter_test.go: markdown output, empty/multiple findings
- review/prompt_test.go: system/user prompt construction
- integration_test.go: full end-to-end flow (build tag: integration)
- .gitea/workflows/ci.yml: test + vet + build on push, dual LLM review on PRs
- CONVENTIONS.md: coding standards for self-review dogfooding
- README.md: usage docs, env vars, architecture

llm/client_test.go

@@ -0,0 +1,110 @@
+package llm
+
+import (
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+)
+
+func TestComplete_Success(t *testing.T) {
+	resp := ChatResponse{
+		Choices: []struct {
+			Message struct {
+				Content string `json:"content"`
+			} `json:"message"`
+		}{
+			{Message: struct {
+				Content string `json:"content"`
+			}{Content: "Hello, world!"}},
+		},
+	}
+
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.URL.Path != "/chat/completions" {
+			t.Errorf("unexpected path: %s", r.URL.Path)
+		}
+		if r.Method != "POST" {
+			t.Errorf("expected POST, got %s", r.Method)
+		}
+		if r.Header.Get("Authorization") != "Bearer test-key" {
+			t.Errorf("unexpected auth: %s", r.Header.Get("Authorization"))
+		}
+		if r.Header.Get("Content-Type") != "application/json" {
+			t.Errorf("unexpected content type: %s", r.Header.Get("Content-Type"))
+		}
+
+		var req ChatRequest
+		if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
+			t.Fatalf("decode request: %v", err)
+		}
+		if req.Model != "gpt-4" {
+			t.Errorf("expected model %q, got %q", "gpt-4", req.Model)
+		}
+		if len(req.Messages) != 1 {
+			t.Errorf("expected 1 message, got %d", len(req.Messages))
+		}
+
+		w.Header().Set("Content-Type", "application/json")
+		json.NewEncoder(w).Encode(resp)
+	}))
+	defer server.Close()
+
+	client := NewClient(server.URL, "test-key", "gpt-4")
+	got, err := client.Complete([]Message{{Role: "user", Content: "Hi"}})
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if got != "Hello, world!" {
+		t.Errorf("expected %q, got %q", "Hello, world!", got)
+	}
+}
+
+func TestComplete_APIError(t *testing.T) {
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusTooManyRequests)
+		w.Write([]byte(`{"error":"rate limited"}`))
+	}))
+	defer server.Close()
+
+	client := NewClient(server.URL, "test-key", "gpt-4")
+	_, err := client.Complete([]Message{{Role: "user", Content: "Hi"}})
+	if err == nil {
+		t.Fatal("expected error for 429, got nil")
+	}
+}
+
+func TestComplete_NoChoices(t *testing.T) {
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Type", "application/json")
+		w.Write([]byte(`{"choices":[]}`))
+	}))
+	defer server.Close()
+
+	client := NewClient(server.URL, "test-key", "gpt-4")
+	_, err := client.Complete([]Message{{Role: "user", Content: "Hi"}})
+	if err == nil {
+		t.Fatal("expected error for no choices, got nil")
+	}
+}
+
+func TestComplete_BadJSON(t *testing.T) {
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Write([]byte(`not json at all`))
+	}))
+	defer server.Close()
+
+	client := NewClient(server.URL, "test-key", "gpt-4")
+	_, err := client.Complete([]Message{{Role: "user", Content: "Hi"}})
+	if err == nil {
+		t.Fatal("expected error for bad JSON, got nil")
+	}
+}
+
+func TestComplete_ServerDown(t *testing.T) {
+	client := NewClient("http://127.0.0.1:1", "test-key", "gpt-4")
+	_, err := client.Complete([]Message{{Role: "user", Content: "Hi"}})
+	if err == nil {
+		t.Fatal("expected error for connection refused, got nil")
+	}
+}