revert(cron): remove per-job profile support (PR #28124) (#43956)

Fully removes the cron per-job 'profile' arg added in #28124: the
cronjob tool schema field, CLI --profile flags on cron create/edit,
job-record storage/validation, the scheduler's _job_profile_context
wrapper, and the script-runner env override. Sequential-partition
logic reverts to workdir-only.

The context-local HERMES_HOME override in hermes_constants and the
subprocess bridging in tools/environments/local.py are kept — they
now have other consumers (dashboard multi-profile, TUI gateway).

tests/hermes_cli/test_cron.py

@@ -55,7 +55,6 @@ class TestCronCommandLifecycle:
                 repeat=None,
                 skill=None,
                 skills=["maps", "blogwatcher"],
-                profile="default",
                 clear_skills=False,
             )
         )
@@ -64,7 +63,6 @@ class TestCronCommandLifecycle:
         assert updated["name"] == "Edited Job"
         assert updated["prompt"] == "Revised prompt"
         assert updated["schedule_display"] == "every 120m"
-        assert updated["profile"] == "default"
 
         cron_command(
             Namespace(
@@ -77,14 +75,12 @@ class TestCronCommandLifecycle:
                 repeat=None,
                 skill=None,
                 skills=None,
-                profile="",
                 clear_skills=True,
             )
         )
         cleared = get_job(job["id"])
         assert cleared["skills"] == []
         assert cleared["skill"] is None
-        assert cleared["profile"] is None
 
         out = capsys.readouterr().out
         assert "Updated job" in out
@@ -100,7 +96,6 @@ class TestCronCommandLifecycle:
                 repeat=None,
                 skill=None,
                 skills=["blogwatcher", "maps"],
-                profile="default",
             )
         )
         out = capsys.readouterr().out
@@ -110,7 +105,6 @@ class TestCronCommandLifecycle:
         assert len(jobs) == 1
         assert jobs[0]["skills"] == ["blogwatcher", "maps"]
         assert jobs[0]["name"] == "Skill combo"
-        assert jobs[0]["profile"] == "default"
 
     def test_list_does_not_crash_when_repeat_is_null(self, tmp_cron_dir, capsys):
         """A one-shot job can be persisted with ``"repeat": null``. `cron