CLI crashes for task parameters starting with run/executor/plugins (e.g. runtime=…): "Run overwrites must start with 'run.'"

Description

Any @run.cli.entrypoint function with a parameter whose name starts with a reserved prefix (run, executor, plugins) cannot be configured from the CLI — the invocation crashes before the task argument parser runs:

ValueError: Run overwrites must start with 'run.'. Got runtime=120

Affected names include runtime, run_id, runs_per_epoch, executors, plugins_dir etc — all normal parameter names.

Steps to reproduce

# app.py
import nemo_run as run

@run.cli.entrypoint(skip_confirmation=True)
def train(runtime: int = 60, lr: float = 0.1):
    print(runtime, lr)

if __name__ == "__main__":
    run.cli.main(train)

$ python app.py runtime=120 lr=0.2
ValueError: Run overwrites must start with 'run.'. Got runtime=120

Unit-level: _parse_prefixed_args(["runtime=3600"], "run") raises.

Expected behavior

runtime is a task parameter, the run should behave like any other name (max_runtime=120 works today). Only run=…, run.…, run[…] (and executor/plugins equivalents) should be treated as prefixed overwrites.

Actual behavior

RunContext.cli_execute passes all task args through _parse_prefixed_args(args, "run"), which matches startswith("run") with no word boundary.

Two more issues in the same function:

• _parse_prefixed_args(["run.a.run.b=1"], "run") returns a.b=1 — every run. occurrence is stripped, silently targeting the wrong parameter.
• _parse_prefixed_args(["executor=k=v"], "executor") returns value k instead of k=v (value split at first =).

Environment

nemo-run main (b85eb67), Python 3.12, macOS

Start with _parse_prefixed_args and its caller, RunContext.cli_execute. Reproduce the unit-level cases for runtime=3600, repeated run. prefixes, and executor=k=v, then trace the existing argument parsing behavior. Done means ordinary task parameters are accepted, only valid leading prefixes are handled, repeated prefixes are not silently removed, and values containing '=' are preserved.