feat: add role title as H1 header for visual differentiation

When reviewer-name is set, prepend "# Security Review" / "# Sonnet Review"
etc. as a top-level header. Makes it immediately obvious which role each
review represents in the Gitea UI, especially when multiple reviews come
from the same bot account.

review/formatter_test.go

@@ -134,3 +134,28 @@ func TestFormatMarkdown_Sentinel(t *testing.T) {
 		t.Error("should not contain sentinel when reviewer name is empty")
 	}
 }
+
+func TestFormatMarkdown_RoleTitle(t *testing.T) {
+	result := &ReviewResult{
+		Verdict:        "APPROVE",
+		Summary:        "All good.",
+		Recommendation: "Merge it.",
+	}
+
+	// With reviewer name: should have title header
+	output := FormatMarkdown(result, "security")
+	if !strings.Contains(output, "# Security Review\n") {
+		t.Error("expected '# Security Review' header when reviewer name is set")
+	}
+
+	output2 := FormatMarkdown(result, "gpt")
+	if !strings.Contains(output2, "# Gpt Review\n") {
+		t.Error("expected '# Gpt Review' header")
+	}
+
+	// Without reviewer name: no title header
+	output3 := FormatMarkdown(result, "")
+	if strings.Contains(output3, "# ") && strings.Contains(output3, " Review\n") {
+		t.Error("should not contain role title header when reviewer name is empty")
+	}
+}