fix: address all review findings (zero remaining)

Tests:
- Add WithTemperature tests (builder method, chaining, zero omission)
- Add temperature serialization tests (omitted when 0, included when set)

Composite action:
- Use python3 for robust JSON version parsing (replaces sed)
- Verify SHA-256 checksum before executing downloaded binary
- Wire up repo input (no longer hardcodes rodin/review-bot)

Release workflow:
- Handle 409 conflict (existing release for tag)
- Use file-based JSON parsing for reliability

Code:
- Tighten WithTemperature doc comment (single clear line)
- Fix flag alignment (missing tab on llmTemp declaration)

llm/client_test.go

@@ -108,3 +108,80 @@ func TestComplete_ServerDown(t *testing.T) {
 		t.Fatal("expected error for connection refused, got nil")
 	}
 }
+
+func TestWithTemperature(t *testing.T) {
+	client := NewClient("http://example.com", "key", "model")
+	if client.Temperature != 0 {
+		t.Errorf("expected initial temperature 0, got %f", client.Temperature)
+	}
+
+	result := client.WithTemperature(0.7)
+	if result != client {
+		t.Error("WithTemperature should return the same client for chaining")
+	}
+	if client.Temperature != 0.7 {
+		t.Errorf("expected temperature 0.7, got %f", client.Temperature)
+	}
+}
+
+func TestComplete_TemperatureOmittedWhenZero(t *testing.T) {
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		var req map[string]interface{}
+		json.NewDecoder(r.Body).Decode(&req)
+
+		if _, exists := req["temperature"]; exists {
+			t.Error("temperature should be omitted when zero (server default)")
+		}
+
+		w.Header().Set("Content-Type", "application/json")
+		json.NewEncoder(w).Encode(ChatResponse{
+			Choices: []struct {
+				Message struct {
+					Content string `json:"content"`
+				} `json:"message"`
+			}{{Message: struct {
+				Content string `json:"content"`
+			}{Content: "ok"}}},
+		})
+	}))
+	defer server.Close()
+
+	client := NewClient(server.URL, "key", "model")
+	_, err := client.Complete([]Message{{Role: "user", Content: "Hi"}})
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+}
+
+func TestComplete_TemperatureIncludedWhenSet(t *testing.T) {
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		var req map[string]interface{}
+		json.NewDecoder(r.Body).Decode(&req)
+
+		temp, exists := req["temperature"]
+		if !exists {
+			t.Error("temperature should be included when set")
+		}
+		if temp != 0.7 {
+			t.Errorf("expected temperature 0.7, got %v", temp)
+		}
+
+		w.Header().Set("Content-Type", "application/json")
+		json.NewEncoder(w).Encode(ChatResponse{
+			Choices: []struct {
+				Message struct {
+					Content string `json:"content"`
+				} `json:"message"`
+			}{{Message: struct {
+				Content string `json:"content"`
+			}{Content: "ok"}}},
+		})
+	}))
+	defer server.Close()
+
+	client := NewClient(server.URL, "key", "model").WithTemperature(0.7)
+	_, err := client.Complete([]Message{{Role: "user", Content: "Hi"}})
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+}