fix(vnc): Bridge erreicht QEMU-VNC (Kern-Bug) + Screenshots ins Projekt

Live-VNC rendert nie, weil die Bridge die VM nie erreichte: QEMU band 127.0.0.1
(Host-Loopback) und host.docker.internal resolved in der Bridge gar nicht.
- aria-vm: --vnc-bind <ip> (Default 127.0.0.1 / env ARIA_VM_VNC_BIND).
- Brain: _docker_gateway() (aus /proc/net/route) → boot bindet VNC an die
  Docker-Gateway-IP (container-erreichbar, NICHT im LAN/Internet).
- docker-compose: bridge bekommt extra_hosts host.docker.internal:host-gateway.
- Screenshot-Endpoint kopiert das PNG zusaetzlich nach
  /shared/projects/<pid>/screenshots/ → erscheint im Dateien-Panel.

End-to-end auf dem Host validiert: Bridge liest den RFB-Handshake
(b'RFB 003.008\n') von der Gateway-gebundenen VNC. aria-vm bereits live.
py/bash clean. Deploy: brain rebuild + bridge NEU (extra_hosts).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

aria-brain/main.py

@@ -946,6 +946,23 @@ def project_file(project_id: str, path: str, binary: bool = False):
 _ARIA_VM_HOST = os.environ.get("ARIA_VM_SSH_HOST", "aria-wohnung")
 
 
+def _docker_gateway() -> str:
+    """Docker-Gateway-IP (= Host-IP auf dem Container-Netz), an die QEMU sein VNC
+    binden soll: von der Bridge erreichbar, aber NICHT im LAN/Internet. Aus
+    /proc/net/route (Default-Route), kein `ip`-Tool noetig."""
+    try:
+        import socket as _sock
+        import struct as _struct
+        with open("/proc/net/route") as f:
+            for line in f.readlines()[1:]:
+                fields = line.strip().split()
+                if len(fields) >= 3 and fields[1] == "00000000" and int(fields[3], 16) & 2:
+                    return _sock.inet_ntoa(_struct.pack("<L", int(fields[2], 16)))
+    except Exception:
+        pass
+    return ""
+
+
 def _ssh_aria_vm(*args: str, timeout: int = 25):
     import subprocess
     cmd = ["ssh", "-o", "StrictHostKeyChecking=no", "-o", "ConnectTimeout=8",
@@ -1038,7 +1055,13 @@ def project_vm_boot(project_id: str, name: str):
     vm = project_vms_mod.get_vm(project_id, name)
     if not vm:
         raise HTTPException(status_code=404, detail=f"VM '{name}' nicht gefunden")
-    rc, out, err = _ssh_aria_vm(*_vm_boot_args(vm), timeout=40)
+    # VNC an die Docker-Gateway-IP binden, damit die Bridge den Stream tunneln
+    # kann (Loopback ist von Containern nicht erreichbar). NICHT im LAN sichtbar.
+    boot_args = _vm_boot_args(vm)
+    gw = _docker_gateway()
+    if gw:
+        boot_args += ["--vnc-bind", gw]
+    rc, out, err = _ssh_aria_vm(*boot_args, timeout=40)
     return {"ok": rc == 0, "name": name, "vnc_port": 5900 + int(vm.get("vnc_display", 1)),
             "output": (out.strip() or err.strip())[:500]}
 
@@ -1074,7 +1097,18 @@ def project_vm_screenshot(project_id: str, name: str):
         raise HTTPException(status_code=500, detail=f"Screenshot-Datei nicht gefunden: {local}")
     with open(local, "rb") as f:
         data = f.read()
+    # Auch ins Projekt kopieren → taucht im Dateien-Panel auf.
+    proj_rel = ""
+    try:
+        shots_dir = os.path.join(_project_dir(project_id), "screenshots")
+        os.makedirs(shots_dir, exist_ok=True)
+        with open(os.path.join(shots_dir, os.path.basename(local)), "wb") as f:
+            f.write(data)
+        proj_rel = "screenshots/" + os.path.basename(local)
+    except Exception:
+        proj_rel = ""
     return {"ok": True, "name": name, "filename": os.path.basename(local),
+            "projectPath": proj_rel,
             "base64": base64.b64encode(data).decode("ascii")}