fix(security): gate /health anonymousKey behind opt-in PROXY_ADVERTISE_ANON_KEY (#109) (#116)

/health is an unauthenticated, LAN-reachable endpoint that returned the live
anonymous bearer key (anonymousKey: PROXY_ANONYMOUS_KEY). Any device that could
reach the port harvested a working, quota-spending credential (P0).

The anonymousKey field is now included only when the caller is localhost (already
fully trusted by the auth path, via the unspoofable req.socket.remoteAddress) OR
the admin explicitly opts in with the new PROXY_ADVERTISE_ANON_KEY=1 env var
(default off). ocp-connect's absent-field fallback (interactive --key / anonymous
access) is unchanged — comment-only update there.

ALIGNMENT.md: this gates an OCP proxy-policy field in /health; it does NOT forward,
add, or alter any Anthropic API operation, so a cli.js citation is N/A under Rule 2.
No blacklisted tokens introduced; alignment.yml passes.

Independent fresh-context reviewer (opus): APPROVE WITH MINOR (Iron Rule 10).

Closes #109.

Co-authored-by: dtzp555 <dtzp555@gmail.com>
Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

ocp-connect

@@ -506,9 +506,11 @@ main() {
   echo ""
 
   # Step 2.5: auto-discover anonymous key from /health (issue #12 §14 Path A).
-  # When the OCP admin set PROXY_ANONYMOUS_KEY, the server advertises it via
-  # /health.anonymousKey. If the user didn't pass --key, use it automatically so
-  # `ocp-connect <host>` works zero-config for OpenClaw multi-agent setups.
+  # The server advertises anonymousKey in /health ONLY when the admin has set
+  # PROXY_ADVERTISE_ANON_KEY=1 (default off — /health is unauthenticated, so
+  # advertising exposes the shared key to any LAN-reachable device; issue #109).
+  # Localhost callers always receive it regardless. When the field is absent,
+  # ocp-connect falls back to anonymous access / interactive --key (step 3 below).
   if [[ -z "$key" ]]; then
     local anon_key
     anon_key=$(echo "$health_json" | python3 -c "