feat(auth): add interactive key policy editing

- Add auth policy to update existing authorized_keys allow policies locally or over remote serve.
- Support key lookup by public key or exact name, with safe, all, server-default, and category-based modes.
- Add questionary-powered interactive key selection and checkbox policy editing with current policy preselected.
- Show policy descriptions in auth keys output so each capability is easier to understand.
- Gate the new remote control command behind the existing keys policy category and include protocol routing/compat updates.
- Bump real-browser-cli to 0.16.2 and lock the new questionary dependency.
- Cover local, remote, validation, and policy-category behavior in tests.

browser_cli/auth/__init__.py

@@ -24,6 +24,7 @@ from browser_cli.auth.keys import (
   load_authorized_keys_with_policies,
   load_private_key,
   public_key_hex,
+  set_authorized_key_policy,
 )
 from browser_cli.auth.pq import (
   new_nonce,
@@ -66,6 +67,7 @@ __all__ = [
   "pq_kex_server_decapsulate",
   "pq_kex_server_keypair",
   "public_key_hex",
+  "set_authorized_key_policy",
   "sign",
   "verify",
 ]

browser_cli/auth/keys.py

@@ -89,3 +89,37 @@ def add_authorized_key(path: Path, pub_hex: str, name: str = "", categories: lis
   with open(path, "a", encoding="utf-8") as file:
     file.write(line)
   return True
+
+def set_authorized_key_policy(path: Path, identifier: str, categories: list[str] | None) -> tuple[str, str] | None:
+  """Update the per-key policy for a trusted key.
+
+  ``identifier`` may be the full public key or an exact key name. ``categories``
+  is written as the ``allow:`` token; ``None`` removes the token so the key uses
+  the server default. Returns ``(pubkey, name)`` for the updated key, ``None`` if
+  no key matched, and raises ``ValueError`` for ambiguous names.
+  """
+  if not path.exists():
+    return None
+
+  wanted = identifier.strip()
+  lines = path.read_text(encoding="utf-8").splitlines(keepends=True)
+  matches: list[tuple[int, str, str, str]] = []
+
+  for index, line in enumerate(lines):
+    parsed = _parse_authorized_line(line)
+    if parsed is None:
+      continue
+    pubkey, name, _cats = parsed
+    if pubkey.lower() == wanted.lower() or (name and name == wanted):
+      newline = "\n" if line.endswith("\n") else ""
+      matches.append((index, pubkey, name, newline))
+
+  if not matches:
+    return None
+  if len(matches) > 1:
+    raise ValueError(f"ambiguous key name: {identifier!r} matches {len(matches)} keys")
+
+  index, pubkey, name, newline = matches[0]
+  lines[index] = format_authorized_line(pubkey, name, categories) + newline
+  path.write_text("".join(lines), encoding="utf-8")
+  return pubkey, name