feat(cron): per-job workdir for project-aware cron runs (#15110)

Cron jobs can now specify a per-job working directory. When set, the job
runs as if launched from that directory: AGENTS.md / CLAUDE.md /
.cursorrules from that dir are injected into the system prompt, and the
terminal / file / code-exec tools use it as their cwd (via TERMINAL_CWD).
When unset, old behaviour is preserved (no project context files, tools
use the scheduler's cwd).

Requested by @bluthcy.

## Mechanism

- cron/jobs.py: create_job / update_job accept 'workdir'; validated to
  be an absolute existing directory at create/update time.
- cron/scheduler.py run_job: if job.workdir is set, point TERMINAL_CWD
  at it and flip skip_context_files to False before building the agent.
  Restored in finally on every exit path.
- cron/scheduler.py tick: workdir jobs run sequentially (outside the
  thread pool) because TERMINAL_CWD is process-global. Workdir-less jobs
  still run in the parallel pool unchanged.
- tools/cronjob_tools.py + hermes_cli/cron.py + hermes_cli/main.py:
  expose 'workdir' via the cronjob tool and 'hermes cron create/edit
  --workdir ...'. Empty string on edit clears the field.

## Validation

- tests/cron/test_cron_workdir.py (21 tests): normalize, create, update,
  JSON round-trip via cronjob tool, tick partition (workdir jobs run on
  the main thread, not the pool), run_job env toggle + restore in finally.
- Full targeted suite (tests/cron/, test_cronjob_tools.py, test_cron.py,
  test_config_cwd_bridge.py, test_worktree.py): 314/314 passed.
- Live smoke: hermes cron create --workdir $(pwd) works; relative path
  rejected; list shows 'Workdir:'; edit --workdir '' clears.

tools/cronjob_tools.py

@@ -217,6 +217,8 @@ def _format_job(job: Dict[str, Any]) -> Dict[str, Any]:
         result["script"] = job["script"]
     if job.get("enabled_toolsets"):
         result["enabled_toolsets"] = job["enabled_toolsets"]
+    if job.get("workdir"):
+        result["workdir"] = job["workdir"]
     return result
 
 
@@ -237,6 +239,7 @@ def cronjob(
     reason: Optional[str] = None,
     script: Optional[str] = None,
     enabled_toolsets: Optional[List[str]] = None,
+    workdir: Optional[str] = None,
     task_id: str = None,
 ) -> str:
     """Unified cron job management tool."""
@@ -275,6 +278,7 @@ def cronjob(
                 base_url=_normalize_optional_job_value(base_url, strip_trailing_slash=True),
                 script=_normalize_optional_job_value(script),
                 enabled_toolsets=enabled_toolsets or None,
+                workdir=_normalize_optional_job_value(workdir),
             )
             return json.dumps(
                 {
@@ -366,6 +370,10 @@ def cronjob(
                 updates["script"] = _normalize_optional_job_value(script) if script else None
             if enabled_toolsets is not None:
                 updates["enabled_toolsets"] = enabled_toolsets or None
+            if workdir is not None:
+                # Empty string clears the field (restores old behaviour);
+                # otherwise pass raw — update_job() validates / normalizes.
+                updates["workdir"] = _normalize_optional_job_value(workdir) or None
             if repeat is not None:
                 # Normalize: treat 0 or negative as None (infinite)
                 normalized_repeat = None if repeat <= 0 else repeat
@@ -470,6 +478,10 @@ Important safety rule: cron-run sessions should not recursively schedule more cr
                 "items": {"type": "string"},
                 "description": "Optional list of toolset names to restrict the job's agent to (e.g. [\"web\", \"terminal\", \"file\", \"delegation\"]). When set, only tools from these toolsets are loaded, significantly reducing input token overhead. When omitted, all default tools are loaded. Infer from the job's prompt — e.g. use \"web\" if it calls web_search, \"terminal\" if it runs scripts, \"file\" if it reads files, \"delegation\" if it calls delegate_task. On update, pass an empty array to clear."
             },
+            "workdir": {
+                "type": "string",
+                "description": "Optional absolute path to run the job from. When set, AGENTS.md / CLAUDE.md / .cursorrules from that directory are injected into the system prompt, and the terminal/file/code_exec tools use it as their working directory — useful for running a job inside a specific project repo. Must be an absolute path that exists. When unset (default), preserves the original behaviour: no project context files, tools use the scheduler's cwd. On update, pass an empty string to clear. Jobs with workdir run sequentially (not parallel) to keep per-job directories isolated."
+            },
         },
         "required": ["action"]
     }
@@ -515,6 +527,7 @@ registry.register(
         reason=args.get("reason"),
         script=args.get("script"),
         enabled_toolsets=args.get("enabled_toolsets"),
+        workdir=args.get("workdir"),
         task_id=kw.get("task_id"),
     ))(),
     check_fn=check_cronjob_requirements,