feat: harden remote serve and reuse connections

- Gate TCP serve commands with safe-by-default policies, per-key allow tokens, per-key rate limiting, and audit labels.
- Reuse authenticated encrypted remote sessions and parallelize/caches multi-browser fanout to reduce repeated handshake roundtrips.
- Increase paged native-host batch size with extension-side byte budgeting to speed large tab listings safely.
- Point install output at public Chrome Web Store / Firefox AMO listings by default, with --dev preserving unpacked workflows.
- Share search-engine metadata between CLI and SDK and bump the package/extension version to 0.16.0.
- Cover the new security, pooling, paging, install, and fanout behavior with expanded Python and extension tests.

browser_cli/serve/control.py

@@ -10,6 +10,7 @@ class ServeControlMixin:
   addr: tuple
   command: str
   auth_keys_path: Path | None
+  auth_label: str | None
 
   async def send_error(self, msg: str, msg_id=None) -> None: ...
   async def send_ok(self, payload, command: str | None = None) -> None: ...
@@ -23,25 +24,32 @@ class ServeControlMixin:
         try:
           clients = send_command("clients.list", profile=target.profile, suppress_pq_warning=True)
           if clients:
-            browser_name = clients[0].get("name")
-            if browser_name:
-              item["browserName"] = browser_name
+            # Carry the full client info so a remote `clients` command can render
+            # from this single roundtrip instead of issuing another clients.list.
+            info = clients[0]
+            for src, dst in (("name", "browserName"), ("version", "version"), ("extensionVersion", "extensionVersion")):
+              value = info.get(src)
+              if value:
+                item[dst] = value
         except Exception:
           pass
         targets.append(item)
       await self.send_ok(targets, self.command)
-      log_request(self.addr, self.command, None, "OK")
+      log_request(self.addr, self.command, None, "OK", identity=self.auth_label)
       return True
 
     if self.command == "browser-cli.auth.keys":
       if self.auth_keys_path is None:
         await self.send_error("no authorized keys file configured on this server")
-        log_request(self.addr, self.command, None, "ERROR", "no authorized keys file")
+        log_request(self.addr, self.command, None, "ERROR", "no authorized keys file", identity=self.auth_label)
         return True
-      from browser_cli.auth import load_authorized_keys_with_names
-      entries = [{"pubkey": pk, "name": name} for pk, name in load_authorized_keys_with_names(self.auth_keys_path)]
+      from browser_cli.auth import load_authorized_keys_with_policies
+      entries = [
+        {"pubkey": pk, "name": name, "allow": cats}
+        for pk, name, cats in load_authorized_keys_with_policies(self.auth_keys_path)
+      ]
       await self.send_ok(entries, self.command)
-      log_request(self.addr, self.command, None, "OK")
+      log_request(self.addr, self.command, None, "OK", identity=self.auth_label)
       return True
 
     if self.command == "browser-cli.auth.trust":
@@ -54,14 +62,27 @@ class ServeControlMixin:
       log_request(self.addr, self.command, None, "ERROR", "no authorized keys file")
       return True
     from browser_cli.auth import add_authorized_key
+    from browser_cli.serve.security import policy_from_categories
     args = msg.get("args") or {}
     pubkey = str(args.get("pubkey") or "")
     name = str(args.get("name") or "")
+    categories = args.get("allow")
     if not re.fullmatch(r"[0-9a-f]{64}", pubkey):
       await self.send_error("invalid pubkey: expected 64 lowercase hex characters")
-      log_request(self.addr, self.command, None, "ERROR", "invalid pubkey")
+      log_request(self.addr, self.command, None, "ERROR", "invalid pubkey", identity=self.auth_label)
       return True
-    added = add_authorized_key(self.auth_keys_path, pubkey, name)
+    if categories is not None:
+      if not isinstance(categories, list):
+        await self.send_error("invalid allow: expected a list of category strings")
+        log_request(self.addr, self.command, None, "ERROR", "invalid allow", identity=self.auth_label)
+        return True
+      try:
+        policy_from_categories(categories)  # validate before persisting
+      except ValueError as exc:
+        await self.send_error(str(exc))
+        log_request(self.addr, self.command, None, "ERROR", "invalid allow category", identity=self.auth_label)
+        return True
+    added = add_authorized_key(self.auth_keys_path, pubkey, name, categories)
     await self.send_ok({"added": added}, self.command)
-    log_request(self.addr, self.command, None, "OK" if added else "ALREADY_TRUSTED")
+    log_request(self.addr, self.command, None, "OK" if added else "ALREADY_TRUSTED", identity=self.auth_label)
     return True