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/cron/test_parallel_pool.py

@@ -172,10 +172,10 @@ class TestSyncMode:
 
 
 class TestSequentialPool:
-    """Sequential (workdir/profile) jobs use the persistent cron-seq pool.
+    """Sequential (workdir) jobs use the persistent cron-seq pool.
 
-    Verifies the follow-up fix: env/context-mutating jobs no longer run inline
-    in the ticker thread, so a long workdir/profile job can't starve the
+    Verifies the follow-up fix: env-mutating jobs no longer run inline
+    in the ticker thread, so a long workdir job can't starve the
     schedule the same way the parallel path used to.
     """