fix(gateway): slash commands never interrupt a running agent (#12334)

Any recognized slash command now bypasses the Level-1 active-session
guard instead of queueing + interrupting. A mid-run /model (or
/reasoning, /voice, /insights, /title, /resume, /retry, /undo,
/compress, /usage, /provider, /reload-mcp, /sethome, /reset) used to
interrupt the agent AND get silently discarded by the slash-command
safety net — zero-char response, dropped tool calls.

Root cause:
- Discord registers 41 native slash commands via tree.command().
- Only 14 were in ACTIVE_SESSION_BYPASS_COMMANDS.
- The other ~15 user-facing ones fell through base.py:handle_message
  to the busy-session handler, which calls running_agent.interrupt()
  AND queues the text.
- After the aborted run, gateway/run.py:9912 correctly identifies the
  queued text as a slash command and discards it — but the damage
  (interrupt + zero-char response) already happened.

Fix:
- should_bypass_active_session() now returns True for any resolvable
  slash command. ACTIVE_SESSION_BYPASS_COMMANDS stays as the subset
  with dedicated Level-2 handlers (documentation + tests).
- gateway/run.py adds a catch-all after the dedicated handlers that
  returns a user-visible "agent busy — wait or /stop first" response
  for any other resolvable command.
- Unknown text / file-path-like messages are unchanged — they still
  queue.

Also:
- gateway/platforms/discord.py logs the invoker identity on every
  slash command (user id + name + channel + guild) so future
  ghost-command reports can be triaged without guessing.

Tests:
- 15 new parametrized cases in test_command_bypass_active_session.py
  cover every previously-broken Discord slash command.
- Existing tests for /stop, /new, /approve, /deny, /help, /status,
  /agents, /background, /steer, /update, /queue still pass.
- test_steer.py's ACTIVE_SESSION_BYPASS_COMMANDS check still passes.

Fixes #5057. Related: #6252, #10370, #4665.

hermes_cli/commands.py

@@ -260,10 +260,10 @@ GATEWAY_KNOWN_COMMANDS: frozenset[str] = frozenset(
 )
 
 
-# Commands that must never be queued behind an active gateway session.
-# These are explicit control/info commands handled by the gateway itself;
-# if they get queued as pending text, the safety net in gateway.run will
-# discard them before they ever reach the user.
+# Commands with explicit Level-2 running-agent handlers in gateway/run.py.
+# Listed here for introspection / tests; semantically a subset of
+# "all resolvable commands" — which is the real bypass set (see
+# should_bypass_active_session below).
 ACTIVE_SESSION_BYPASS_COMMANDS: frozenset[str] = frozenset(
     {
         "agents",
@@ -285,9 +285,26 @@ ACTIVE_SESSION_BYPASS_COMMANDS: frozenset[str] = frozenset(
 
 
 def should_bypass_active_session(command_name: str | None) -> bool:
-    """Return True when a slash command must bypass active-session queuing."""
-    cmd = resolve_command(command_name) if command_name else None
-    return bool(cmd and cmd.name in ACTIVE_SESSION_BYPASS_COMMANDS)
+    """Return True for any resolvable slash command.
+
+    Rationale: every gateway-registered slash command either has a
+    specific Level-2 handler in gateway/run.py (/stop, /new, /model,
+    /approve, etc.) or reaches the running-agent catch-all that returns
+    a "busy — wait or /stop first" response. In both paths the command
+    is dispatched, not queued.
+
+    Queueing is always wrong for a recognized slash command because the
+    safety net in gateway.run discards any command text that reaches
+    the pending queue — which meant a mid-run /model (or /reasoning,
+    /voice, /insights, /title, /resume, /retry, /undo, /compress,
+    /usage, /provider, /reload-mcp, /sethome, /reset) would silently
+    interrupt the agent AND get discarded, producing a zero-char
+    response. See issue #5057 / PRs #6252, #10370, #4665.
+
+    ACTIVE_SESSION_BYPASS_COMMANDS remains the subset of commands with
+    explicit Level-2 handlers; the rest fall through to the catch-all.
+    """
+    return resolve_command(command_name) is not None if command_name else False
 
 
 def _resolve_config_gates() -> set[str]: