feat: add hermes cron run --now for immediate job execution (closes #347)

Problem: 'hermes cron run JOBID' only queues for next scheduler tick.
Stale error state (like tool_choice TypeError residue) persists forever
because there's no way to execute a job immediately and get fresh results.

Solution: Three-layer synchronous execution path:
- cron/jobs.py: run_job_now() calls scheduler.run_job() then mark_job_run()
- gateway: POST /api/jobs/{id}/run-now endpoint (runs in thread executor)
- CLI: hermes cron run JOBID --now executes and prints result immediately
- tools/cronjob_tools.py: 'run_now' action routes to new function

Also fixes #346, #349 (same stale error pattern).

gateway/platforms/api_server.py

@@ -973,6 +973,7 @@ class APIServerAdapter(BasePlatformAdapter):
             pause_job as _cron_pause,
             resume_job as _cron_resume,
             trigger_job as _cron_trigger,
+            run_job_now as _cron_run_now,
         )
         # Wrap as staticmethod to prevent descriptor binding — these are plain
         # module functions, not instance methods.  Without this, self._cron_*()
@@ -986,6 +987,7 @@ class APIServerAdapter(BasePlatformAdapter):
         _cron_pause = staticmethod(_cron_pause)
         _cron_resume = staticmethod(_cron_resume)
         _cron_trigger = staticmethod(_cron_trigger)
+        _cron_run_now = staticmethod(_cron_run_now)
         _CRON_AVAILABLE = True
     except ImportError:
         pass
@@ -1204,6 +1206,28 @@ class APIServerAdapter(BasePlatformAdapter):
         except Exception as e:
             return web.json_response({"error": str(e)}, status=500)
 
+    async def _handle_run_job_now(self, request: "web.Request") -> "web.Response":
+        """POST /api/jobs/{job_id}/run-now — execute job synchronously and return result."""
+        auth_err = self._check_auth(request)
+        if auth_err:
+            return auth_err
+        cron_err = self._check_jobs_available()
+        if cron_err:
+            return cron_err
+        job_id, id_err = self._check_job_id(request)
+        if id_err:
+            return id_err
+        try:
+            import asyncio as _asyncio
+            result = await _asyncio.get_event_loop().run_in_executor(
+                None, self._cron_run_now, job_id
+            )
+            if result is None:
+                return web.json_response({"error": "Job not found"}, status=404)
+            return web.json_response(result)
+        except Exception as e:
+            return web.json_response({"error": str(e)}, status=500)
+
     # ------------------------------------------------------------------
     # Output extraction helper
     # ------------------------------------------------------------------
@@ -1565,6 +1589,7 @@ class APIServerAdapter(BasePlatformAdapter):
             self._app.router.add_post("/api/jobs/{job_id}/pause", self._handle_pause_job)
             self._app.router.add_post("/api/jobs/{job_id}/resume", self._handle_resume_job)
             self._app.router.add_post("/api/jobs/{job_id}/run", self._handle_run_job)
+            self._app.router.add_post("/api/jobs/{job_id}/run-now", self._handle_run_job_now)
             # Structured event streaming
             self._app.router.add_post("/v1/runs", self._handle_runs)
             self._app.router.add_get("/v1/runs/{run_id}/events", self._handle_run_events)