feat(submit): update_pending_job tool for editing PENDING submissions

Add an update_pending_job MCP tool that lets callers modify parameters
of a PENDING submission before confirm_submit_job:
  - queue, executor_memory, executor_cores, num_executors
  - app_name
  - extra_args
  - script_path (re-validates file existence and SQL guard)

Only PENDING submissions can be updated; SUBMITTED/CANCELLED/FAILED are
rejected with HTTP 400.

spark_executor/tools/requests.py

@@ -75,6 +75,20 @@ class PendingIdRequest(BaseModel):
     pending_id: str
 
 
+class UpdatePendingJobRequest(BaseModel):
+    pending_id: str
+    script_path: str | None = Field(
+        default=None,
+        description="Optional new absolute path to the PySpark script. If provided, the file must exist and pass SQL guard.",
+    )
+    queue: str | None = None
+    executor_memory: str | None = None
+    executor_cores: int | None = None
+    num_executors: int | None = None
+    app_name: str | None = None
+    extra_args: dict[str, str] | None = None
+
+
 class JobIdRequest(BaseModel):
     job_id: str
 

spark_executor/tools/submit.py

@@ -287,3 +287,55 @@ def cancel_pending_job(pending_id: str) -> dict[str, str]:
     pending_store.save(p)
     logger.info(f"cancel_pending_job ok pending_id={pending_id}")
     return {"pending_id": pending_id, "status": "CANCELLED"}
+
+
+def update_pending_job(
+    *,
+    pending_id: str,
+    script_path: str | None = None,
+    queue: str | None = None,
+    executor_memory: str | None = None,
+    executor_cores: int | None = None,
+    num_executors: int | None = None,
+    app_name: str | None = None,
+    extra_args: dict[str, str] | None = None,
+) -> dict[str, object]:
+    logger.debug(f"update_pending_job enter pending_id={pending_id}")
+    pending = pending_store.get(pending_id)
+    if pending is None:
+        raise KeyError(f"Unknown pending_id: {pending_id}")
+    if pending.status != "PENDING":
+        raise ValueError(
+            f"pending_id {pending_id} is in status {pending.status!r}; "
+            f"only PENDING submissions can be updated"
+        )
+
+    if script_path is not None:
+        _check_script_path(script_path)
+        with open(script_path, encoding="utf-8") as f:
+            script_body = f.read()
+        offenses = validate_pyspark_code(script_body)
+        if offenses:
+            logger.warning(
+                f"update_pending_job rejected: SQL policy violation(s) in "
+                f"{script_path}: {offenses}"
+            )
+            raise _sql_guard_error(offenses)
+        pending.script_path = script_path
+
+    if queue is not None:
+        pending.queue = queue
+    if executor_memory is not None:
+        pending.executor_memory = executor_memory
+    if executor_cores is not None:
+        pending.executor_cores = executor_cores
+    if num_executors is not None:
+        pending.num_executors = num_executors
+    if app_name is not None:
+        pending.app_name = app_name
+    if extra_args is not None:
+        pending.extra_args = dict(extra_args)
+
+    pending_store.save(pending)
+    logger.info(f"update_pending_job ok pending_id={pending_id}")
+    return {"pending_id": pending_id, "status": pending.status, "parameters": pending.model_dump()}