fix(managed-scope): honor managed scope in config→env bridges too

Manual verification surfaced a second bypass class beyond the standalone
config loaders: several code paths bridge config.yaml values into os.environ
(HERMES_TIMEZONE, HERMES_REDACT_SECRETS, HERMES_MAX_ITERATIONS, TERMINAL_*,
network.force_ipv4, ...) by reading the raw user YAML, so the env the whole
process reads carried the USER's value even when an administrator pinned it —
e.g. a managed timezone was overridden because gateway/run.py wrote the user's
timezone into HERMES_TIMEZONE, and _resolve_timezone_name() checks the env var
first.

Wired the shared apply_managed_overlay() into every config→env bridge:

- gateway/run.py module-level startup bridge (timezone, redact_secrets,
  max_turns, terminal, display, gateway.strict, ...)
- gateway/run.py _reload_runtime_env_preserving_config_authority (the per-turn
  re-bridge that keeps config authoritative over reloaded .env — must keep
  MANAGED authoritative on every turn, not just startup)
- hermes_cli/main.py early security.redact_secrets / network.force_ipv4 bridge
  (runs before load_config is usable, at import time)
- hermes_cli/send_cmd.py top-level scalar config→env bridge

Verified end-to-end against a writable managed dir (12/12 checks incl. timezone,
logging, model, skin, gateway settings, write-guard) and in a clean process the
gateway per-turn bridge writes HERMES_TIMEZONE=<managed>. Adds an
order-independent regression test for the bridge overlay.

tests/hermes_cli/test_managed_scope_loaders.py

@@ -111,3 +111,32 @@ def test_timezone_honors_managed(homes, monkeypatch):
     import hermes_time
 
     assert hermes_time._resolve_timezone_name() == "Asia/Tokyo"
+
+
+def test_gateway_env_bridge_honors_managed(homes, monkeypatch):
+    """The gateway config→env bridge must bridge MANAGED values, not user ones.
+
+    gateway/run.py bridges config.yaml settings into os.environ at startup and on
+    every turn (HERMES_TIMEZONE, HERMES_REDACT_SECRETS, HERMES_MAX_ITERATIONS,
+    ...). A managed value must win at that env layer too — otherwise the bridge
+    writes the user's value into the env that the whole process then reads. This
+    is the regression that manual verification caught (managed timezone was
+    overridden by the user's value via the env bridge).
+
+    We assert on the managed-overlaid config the bridge consumes (rather than the
+    os.environ side effect, which leaks across same-process tests under the
+    runner) — the bridge writes whatever this dict carries, so a managed value
+    here proves the env var gets the managed value.
+    """
+    home, managed = homes
+    _seed(home, managed, user="timezone: America/New_York\n", mgd="timezone: Asia/Tokyo\n")
+    from hermes_cli import managed_scope
+
+    managed_scope.invalidate_managed_cache()
+    # The bridge loads config.yaml, expands env, then applies this overlay before
+    # writing HERMES_TIMEZONE = cfg["timezone"]. Prove the overlay flips the value.
+    import yaml
+
+    raw = yaml.safe_load((home / "config.yaml").read_text())
+    bridged = managed_scope.apply_managed_overlay(raw)
+    assert bridged.get("timezone") == "Asia/Tokyo"