fix(gateway): also tolerate malformed env vars in custom human-delay mode

Widens @Krionex's PR #16933 fix to cover the second bug class at the sibling
site. natural mode used to pass env values through int() before the PR
caught mis-typed values crashing the gateway; custom mode had the exact
same bug one branch away (HERMES_HUMAN_DELAY_MIN_MS=oops in custom mode
still crashed). Same try/except/fallback pattern, scoped to the two
int() calls that feed random.uniform().

tests/gateway/test_platform_base.py

@@ -512,6 +512,17 @@ class TestGetHumanDelay:
             delay = BasePlatformAdapter._get_human_delay()
             assert 0.1 <= delay <= 0.2
 
+    def test_custom_mode_tolerates_malformed_env_vars(self):
+        env = {
+            "HERMES_HUMAN_DELAY_MODE": "custom",
+            "HERMES_HUMAN_DELAY_MIN_MS": "oops",
+            "HERMES_HUMAN_DELAY_MAX_MS": "still-bad",
+        }
+        with patch.dict(os.environ, env):
+            # falls back to the custom-mode defaults instead of crashing
+            delay = BasePlatformAdapter._get_human_delay()
+            assert 0.8 <= delay <= 2.5
+
 
 # ---------------------------------------------------------------------------
 # utf16_len / _prefix_within_utf16_limit / truncate_message with len_fn