fix: thread safety for concurrent subagent delegation (#1672)

* fix: thread safety for concurrent subagent delegation

Four thread-safety fixes that prevent crashes and data races when
running multiple subagents concurrently via delegate_task:

1. Remove redirect_stdout/stderr from delegate_tool — mutating global
   sys.stdout races with the spinner thread when multiple children start
   concurrently, causing segfaults. Children already run with
   quiet_mode=True so the redirect was redundant.

2. Split _run_single_child into _build_child_agent (main thread) +
   _run_single_child (worker thread). AIAgent construction creates
   httpx/SSL clients which are not thread-safe to initialize
   concurrently.

3. Add threading.Lock to SessionDB — subagents share the parent's
   SessionDB and call create_session/append_message from worker threads
   with no synchronization.

4. Add _active_children_lock to AIAgent — interrupt() iterates
   _active_children while worker threads append/remove children.

5. Add _client_cache_lock to auxiliary_client — multiple subagent
   threads may resolve clients concurrently via call_llm().

Based on PR #1471 by peteromallet.

* feat: Honcho base_url override via config.yaml + quick command alias type

Two features salvaged from PR #1576:

1. Honcho base_url override: allows pointing Hermes at a remote
   self-hosted Honcho deployment via config.yaml:

     honcho:
       base_url: "http://192.168.x.x:8000"

   When set, this overrides the Honcho SDK's environment mapping
   (production/local), enabling LAN/VPN Honcho deployments without
   requiring the server to live on localhost. Uses config.yaml instead
   of env var (HONCHO_URL) per project convention.

2. Quick command alias type: adds a new 'alias' quick command type
   that rewrites to another slash command before normal dispatch:

     quick_commands:
       sc:
         type: alias
         target: /context

   Supports both CLI and gateway. Arguments are forwarded to the
   target command.

Based on PR #1576 by redhelix.

---------

Co-authored-by: peteromallet <peteromallet@users.noreply.github.com>
Co-authored-by: redhelix <redhelix@users.noreply.github.com>

tests/test_quick_commands.py

@@ -47,6 +47,28 @@ class TestCLIQuickCommands:
         args = cli.console.print.call_args[0][0]
         assert "no output" in args.lower()
 
+    def test_alias_command_routes_to_target(self):
+        """Alias quick commands rewrite to the target command."""
+        cli = self._make_cli({"shortcut": {"type": "alias", "target": "/help"}})
+        with patch.object(cli, "process_command", wraps=cli.process_command) as spy:
+            cli.process_command("/shortcut")
+            # Should recursively call process_command with /help
+            spy.assert_any_call("/help")
+
+    def test_alias_command_passes_args(self):
+        """Alias quick commands forward user arguments to the target."""
+        cli = self._make_cli({"sc": {"type": "alias", "target": "/context"}})
+        with patch.object(cli, "process_command", wraps=cli.process_command) as spy:
+            cli.process_command("/sc some args")
+            spy.assert_any_call("/context some args")
+
+    def test_alias_no_target_shows_error(self):
+        cli = self._make_cli({"broken": {"type": "alias", "target": ""}})
+        cli.process_command("/broken")
+        cli.console.print.assert_called_once()
+        args = cli.console.print.call_args[0][0]
+        assert "no target defined" in args.lower()
+
     def test_unsupported_type_shows_error(self):
         cli = self._make_cli({"bad": {"type": "prompt", "command": "echo hi"}})
         cli.process_command("/bad")