feat: Multiple attachments + paste support (App + Diagnostic)

App:
- Multiple pending attachments (horizontal scroll preview)
- Individual remove (X) or clear all
- Send button shows when any attachment pending
- All files sent before text message

Diagnostic:
- Clip icon for file selection (multiple)
- Paste images/files from clipboard (Ctrl+V)
- Pending preview with thumbnails
- Files sent via RVS before text message

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

diagnostic/server.js

@@ -1181,6 +1181,14 @@ wss.on("connection", (ws) => {
         if (ws._sshSock) ws._sshSock.write(msg.data);
       } else if (msg.action === "live_ssh_close") {
         if (ws._sshSock) { ws._sshSock.end(); ws._sshSock = null; }
+      } else if (msg.action === "send_file") {
+        // Datei von Diagnostic an Bridge via RVS senden
+        sendToRVS_raw({
+          type: "file",
+          payload: { name: msg.name, type: msg.type, size: msg.size, base64: msg.base64 },
+          timestamp: Date.now(),
+        });
+        log("info", "server", `Datei gesendet: ${msg.name} (${msg.type})`);
       } else if (msg.action === "cancel_request") {
         // Laufende Anfrage abbrechen — doctor --fix beendet stuck runs
         log("warn", "server", "Anfrage abgebrochen — fuehre doctor --fix aus");