fix: sanitize mermaid member syntax (colons, angle brackets, refs)

crates/adapters/mermaid/src/mermaid_renderer.rs

@@ -136,10 +136,10 @@ impl MermaidRenderer {
         }
         let name = element.name();
         for field in element.fields() {
-            member_target.push(format!("    {name} : {field}"));
+            member_target.push(format!("    {name} : {}", sanitize_member(field)));
         }
         for method in element.methods() {
-            member_target.push(format!("    {name} : {method}"));
+            member_target.push(format!("    {name} : {}", sanitize_member(method)));
         }
     }
 
@@ -274,6 +274,20 @@ impl MermaidRenderer {
     }
 }
 
+// Sanitize a field/method string for Mermaid classDiagram member syntax.
+// Mermaid uses `ClassName : member` — it cannot handle colons inside the
+// member (Rust's `field: Type`), nor reference/lifetime syntax (`&`, `'`),
+// nor angle-bracket generics (`<`, `>`).
+fn sanitize_member(s: &str) -> String {
+    // Convert `name: Type` → `name Type` (drop the colon)
+    let no_colon = s.replace(": ", " ").replace(':', " ");
+    // Strip chars that break the Mermaid grammar
+    no_colon
+        .replace(['&', '\''], "")
+        .replace('<', "[")
+        .replace('>', "]")
+}
+
 impl DiagramRenderer for MermaidRenderer {
     fn render(&self, graph: &CodeGraph) -> Result<RenderOutput, DomainError> {
         let content = match self.level {