Add image paste support for xterm.js terminal

Intercept clipboard paste events containing images in the terminal,
upload them into the Docker container via bollard's tar upload API,
and inject the resulting file path into terminal stdin so Claude Code
can reference the image.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/src/hooks/useTerminal.ts

@@ -49,6 +49,14 @@ export function useTerminal() {
     [],
   );
 
+  const pasteImage = useCallback(
+    async (sessionId: string, imageData: Uint8Array) => {
+      const bytes = Array.from(imageData);
+      return commands.pasteImageToTerminal(sessionId, bytes);
+    },
+    [],
+  );
+
   const onOutput = useCallback(
     (sessionId: string, callback: (data: Uint8Array) => void) => {
       const eventName = `terminal-output-${sessionId}`;
@@ -76,6 +84,7 @@ export function useTerminal() {
     open,
     close,
     sendInput,
+    pasteImage,
     resize,
     onOutput,
     onExit,