fix(honcho): plug pinPeerName transition gaps

Three correctness gaps when honcho.json's identity-mapping config changes
mid-flight:

1. The gateway's agent cache signature ignored honcho identity keys, so
   editing peerName / pinPeerName / userPeerAliases / runtimePeerPrefix
   was silently dropped until an unrelated cache eviction. Extend
   _extract_cache_busting_config to fingerprint the resolved honcho
   config so the AIAgent rebuilds on the next message.

2. cmd_setup let single → multi flips orphan the pinned-pool history
   under peerName without warning. Detect the transition, warn that
   runtime users will resolve to fresh empty peers, and auto-steer to
   hybrid (alias the operator's runtime IDs back to peerName) so the
   operator's own continuity survives. yes / no overrides available.

3. README didn't document the orphaning behaviour. Add a "Migrating
   single → multi" callout under Deployment shapes.

Tests:
- TestPinTransition (test_pin_peer_name.py): fresh-manager flip resolves
  to runtime, in-process flip is gated by the per-key session cache
  (documents the gateway-cache-must-bust contract), 3 cache-bust
  signature tests for pin / aliases / prefix.
- TestProfilePeerUniqueness: two profiles pinned to distinct peerNames
  resolve to distinct peers; host-level peerName overrides root when
  pinned.
- test_single_to_multi_steers_to_hybrid_by_default and
  test_single_to_multi_yes_override_keeps_multi (test_cli.py): wizard
  guard end-to-end coverage.

gateway/run.py

@@ -15071,6 +15071,26 @@ class GatewayRunner:
             out["tools.registry_generation"] = getattr(registry, "_generation", None)
         except Exception:
             out["tools.registry_generation"] = None
+
+        # Honcho identity-mapping keys live in honcho.json, not user_config.
+        # HonchoSessionManager freezes the resolved peer_name / pin / aliases /
+        # prefix at construction; without busting here, mid-flight honcho.json
+        # edits go unread until the next unrelated cache eviction.
+        try:
+            from plugins.memory.honcho.client import HonchoClientConfig
+
+            hcfg = HonchoClientConfig.from_global_config()
+            out["honcho.peer_name"] = hcfg.peer_name
+            out["honcho.pin_peer_name"] = bool(hcfg.pin_peer_name)
+            out["honcho.runtime_peer_prefix"] = hcfg.runtime_peer_prefix or ""
+            aliases = hcfg.user_peer_aliases or {}
+            out["honcho.user_peer_aliases"] = sorted(aliases.items()) if isinstance(aliases, dict) else []
+        except Exception:
+            out["honcho.peer_name"] = None
+            out["honcho.pin_peer_name"] = None
+            out["honcho.runtime_peer_prefix"] = None
+            out["honcho.user_peer_aliases"] = None
+
         return out
 
     @staticmethod