## Description
On macOS 26.x, `launchctl bootstrap` and `launchctl kickstart` return exit code 5 ("Input/output error"), which Hermes already anticipates and handles by spawning a detached fallback process. However, the gateway status reporting is ambiguous:
- `gateway status` says "Gateway service is loaded" (because `launchctl list` returns exit 0)
- But `launchctl print` shows `state = not running` — launchd isn't actually supervising anything
- The detached fallback PID running is invisible to the status command
- Users can't tell whether auto-start at login and auto-restart on crash are available
### Root Cause
Two problems in `hermes_cli/gateway.py`:
1. **`_probe_launchd_service_running()`** (line 1067): Determined launchd service liveness solely by `launchctl list <label>` exit code. On macOS 26, this returns 0 even when the service is only *registered* but not running (output lacks a `"PID"` field). This caused `GatewayRuntimeSnapshot.service_running = True` incorrectly, which suppressed the process/service mismatch warning.
2. **`launchd_status()`** (line 3569): Used the same binary "loaded/not loaded" check without inspecting whether launchd actually has a PID, whether a detached fallback is running, or whether auto-start/restart are available.
### Changes
**`hermes_cli/gateway.py`:**
1. **New `_parse_launchd_pid_from_list_output()` helper** — Extracts the PID from `launchctl list` output. When launchd is actively supervising, the output includes `"PID" = <number>;`. When only registered but not running, no PID field is present.
2. **Fixed `_probe_launchd_service_running()`** — Now requires a PID in the `launchctl list` output to confirm launchd is actually supervising. This correctly sets `service_running = False` when launchd has the service registered but `state = not running`, which triggers the existing process/service mismatch detection.
3. **Reworked `launchd_status()`** — Reports clearly separated information:
- LaunchAgent plist currentness (stale or current)
- Whether launchd is actively supervising (with PID)
- Whether a detached fallback PID is running
- Whether auto-start at login and auto-restart on crash are available
- When launchd supervision is known to be unavailable, explains why
4. **Persistent unsupported marker** (`~/.hermes/.gateway-launchd-unsupported`) — Written when `_launchd_fallback_to_detached()` is called (launchd exit 5/125). Allows `launchd_status()` to explain *why* launchd can't supervise even when no fallback process is currently running. Cleared automatically when a future bootstrap/kickstart succeeds (e.g., after an OS update fixes the issue).
5. **Updated `_print_gateway_process_mismatch()`** — Distinguishes the managed detached fallback from a genuinely manual `nohup hermes gateway run`, providing accurate guidance for each case.
### Status Output Examples
**Before** (macOS 26, fallback active):
```
Launchd plist: ~/Library/LaunchAgents/ai.hermes.gateway.plist
✓ Service definition matches the current Hermes install
✓ Gateway service is loaded
{
"Label" = "ai.hermes.gateway";
"OnDemand" = true;
...
};
```
**After** (macOS 26, fallback active):
```
Launchd plist: ~/Library/LaunchAgents/ai.hermes.gateway.plist
✓ Service definition matches the current Hermes install
⚠ Gateway service is registered but launchd is not supervising it
launchd cannot manage the gateway on this macOS version.
✓ Detached fallback process is running (PID 12345)
Cron jobs will fire. Stop with: hermes gateway stop
⚠ Auto-start at login and auto-restart on crash are NOT available.
```
**After** (normal launchd supervision):
```
Launchd plist: ~/Library/LaunchAgents/ai.hermes.gateway.plist
✓ Service definition matches the current Hermes install
✓ Gateway is supervised by launchd (PID 12345)
Auto-start at login and auto-restart on crash are available.
```
### Tests
Updated 5 existing tests and added 11 new tests in `tests/hermes_cli/test_gateway_service.py`:
- PID parsing from `launchctl list` output (with PID, without PID, empty, unquoted PID)
- `_probe_launchd_service_running()` requires PID presence
- Unsupport marker lifecycle (write, clear, persist across fallback)
- Marker cleared on successful bootstrap
- `launchd_status()` reporting: supervised, fallback-running, fallback-unavailable
- Existing fallback tests now verify marker creation
### Related Issues
- Issue #23387 (original macOS 26 launchd workaround)
- Issue #42524 (this issue)
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