app: autorun mode (unattended run + upload + auto-exit); IPv6 severity rework

IPv6: absence is no longer a defect. If the network never provisioned v6
(no global address, no ::/0 route) the finding is ipv6.not_offered at INFO
(green) — most networks are still IPv4-only. If v6 IS advertised but
doesn't work, it's ipv6.broken at MEDIUM (yellow), because half-working v6
stalls connections. Verified on-device: our LAN advertises a v6 default
route with no path, and now reports ipv6.broken.

Autorun: `am start ... --ez autorun true` runs the suite immediately,
POSTs the report to the collection endpoint, shows the result for 3s and
finishes the activity (stays open if the upload failed). receiver.py gains
POST /report + GET /reports + GET /report/<name>. Verified end to end: one
adb command, report retrieved over HTTP, app closed itself.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

tools/adb-beacon/receiver.py

@@ -18,6 +18,7 @@ import time
 from http.server import BaseHTTPRequestHandler, ThreadingHTTPServer
 
 STATE_PATH = os.environ.get("STATE_PATH", "/run/echolot-adb-beacon.json")
+REPORT_DIR = os.environ.get("REPORT_DIR", "/tmp/echolot-reports")
 SECRET = os.environ.get("ECHOLOT_BEACON_SECRET", "")
 BIND = os.environ.get("BEACON_BIND", "0.0.0.0")
 PORT = int(os.environ.get("BEACON_PORT", "9099"))
@@ -55,6 +56,19 @@ class Handler(BaseHTTPRequestHandler):
         # Dev convenience: serve a staged APK so a device (which can only reach
         # this host on 443) can pull it via its own curl — more resilient than
         # adb's sustained transport over a flaky wifi. Path from APK_PATH.
+        if p == "/reports":
+            try:
+                names = sorted(os.listdir(REPORT_DIR), reverse=True)
+            except FileNotFoundError:
+                names = []
+            return self._send(200, json.dumps(names).encode())
+        if p.startswith("/report/"):
+            name = os.path.basename(p[len("/report/"):])
+            try:
+                with open(os.path.join(REPORT_DIR, name), "rb") as f:
+                    return self._send(200, f.read())
+            except FileNotFoundError:
+                return self._send(404, b'{"error":"no such report"}')
         if p == "/apk":
             apk = os.environ.get("APK_PATH", "/tmp/echolot-app.apk")
             try:
@@ -65,7 +79,27 @@ class Handler(BaseHTTPRequestHandler):
         return self._send(404, b'{"error":"not found"}')
 
     def do_POST(self):
-        if self.path.rstrip("/") != "/beacon":
+        p = self.path.rstrip("/")
+        # Measurement-report drop box: the app's autorun mode POSTs its run JSON here so a
+        # test run needs no adb at all (start it once, collect the result over HTTP).
+        if p == "/report":
+            if SECRET and self.headers.get("X-Beacon-Secret") != SECRET:
+                return self._send(403, b'{"error":"bad secret"}')
+            n = int(self.headers.get("Content-Length", "0"))
+            body = self.rfile.read(n)
+            try:
+                doc = json.loads(body)
+                dev = doc.get("run", {}).get("device", {}).get("model", "device")
+                rid = doc.get("run", {}).get("id", "unknown")[:8]
+            except Exception:
+                dev, rid = "device", "unparsed"
+            os.makedirs(REPORT_DIR, exist_ok=True)
+            name = f"{int(time.time())}-{dev}-{rid}.json"
+            with open(os.path.join(REPORT_DIR, name), "wb") as f:
+                f.write(body)
+            return self._send(200, json.dumps({"stored": name, "bytes": len(body)}).encode())
+
+        if p != "/beacon":
             return self._send(404, b'{"error":"not found"}')
         if SECRET and self.headers.get("X-Beacon-Secret") != SECRET:
             return self._send(403, b'{"error":"bad secret"}')