Adds a regression test verifying that /background bypasses the
active-session guard in the platform adapter, matching the existing
test pattern for /stop, /new, /approve, /deny, and /status.
* fix(gateway): /stop and /new bypass Level 1 active-session guard
The base adapter's Level 1 guard intercepted ALL messages while an
agent was running, including /stop and /new. These commands were queued
as pending messages instead of being dispatched to the gateway runner's
Level 2 handler. When the agent eventually stopped (via the interrupt
mechanism), the command text leaked into the conversation as a user
message — the model would receive '/stop' as input and respond to it.
Fix: Add /stop, /new, and /reset to the bypass set in base.py alongside
/approve, /deny, and /status. Consolidate the three separate bypass
blocks into one. Commands in the bypass set are dispatched inline to the
gateway runner, where Level 2 handles them correctly (hard-kill for
/stop, session reset for /new).
Also add a safety net in _run_agent's pending-message processing: if the
pending text resolves to a known slash command, discard it instead of
passing it to the agent. This catches edge cases where command text
leaks through the interrupt_message fallback.
Refs: #5244
* test: regression tests for command bypass of active-session guard
17 tests covering:
- /stop, /new, /reset bypass the Level 1 guard when agent is running
- /approve, /deny, /status bypass (existing behavior, now tested)
- Regular text and unknown commands still queued (not bypassed)
- File paths like '/path/to/file' not treated as commands
- Telegram @botname suffix handled correctly
- Safety net command resolution (resolve_command detects known commands)
