fix: remove code block language label overlap, add diagram zoom/pan/fullscreen

- Remove 'bash' language label that overlapped with code text
- Add zoom (scroll), pan (drag), and fullscreen toggle to Mermaid diagrams
- Fullscreen mode with dark overlay, controls toolbar, and Esc to close
- Zoom percentage indicator and reset button

apps/web/src/components/code-block.tsx

@@ -20,7 +20,6 @@ export function CodeBlock({ children, className, inline }: CodeBlockProps) {
     );
   }
 
-  const language = className?.replace("language-", "") || "";
   const codeString = String(children).replace(/\n$/, "");
 
   const handleCopy = async () => {
@@ -31,11 +30,6 @@ export function CodeBlock({ children, className, inline }: CodeBlockProps) {
 
   return (
     <div className="relative group my-4">
-      {language && (
-        <div className="absolute top-0 left-0 px-3 py-1 text-[10px] font-medium uppercase tracking-wider text-zinc-500 bg-black/30 rounded-tl-lg rounded-br-lg border-b border-r border-white/5">
-          {language}
-        </div>
-      )}
       <button
         onClick={handleCopy}
         className="absolute top-2 right-2 p-1.5 rounded-md bg-white/5 border border-white/10 text-zinc-500 hover:text-white hover:bg-white/10 transition-all opacity-0 group-hover:opacity-100 z-10"
@@ -47,7 +41,7 @@ export function CodeBlock({ children, className, inline }: CodeBlockProps) {
           <Copy className="w-3.5 h-3.5" />
         )}
       </button>
-      <pre className="overflow-x-auto rounded-lg bg-black/50 border border-white/10 p-4 pt-8 text-sm leading-relaxed font-mono scrollbar-thin">
+      <pre className="overflow-x-auto rounded-lg bg-black/50 border border-white/10 p-4 text-sm leading-relaxed font-mono scrollbar-thin">
         <code className={`text-zinc-300 ${className || ""}`}>{codeString}</code>
       </pre>
     </div>