fix(gateway): use transcript timestamp for auto-continue freshness

Follow-up to PR #16802 (BeliefanX). The original fix read
`agent_history[-1].get("timestamp")` for the tool-tail freshness gate,
but `gateway/run.py` strips the `timestamp` field off all tool/tool_call
rows when building `agent_history` from the raw transcript (see
`clean_msg = {k: v for k, v in msg.items() if k != "timestamp"}`).  At
runtime the tool-tail branch always saw `None` and silently took the
legacy-fresh path — the stale-guard never fired for the tool-tail case
it was supposed to cover.

Changes:
- Read the freshness signal from the RAW `history` list (via new
  `_last_transcript_timestamp()` helper) BEFORE the strip.  Both the
  resume_pending branch and the tool-tail branch use this single signal,
  replacing the two divergent ones.
- Default window bumped 15 min → 1 hour via new
  `_AUTO_CONTINUE_FRESHNESS_SECS_DEFAULT`.  The 15-minute default was
  shorter than the default `gateway_timeout` of 30 min, so a legitimate
  long-running turn interrupted near its timeout boundary and resumed
  shortly after would have been misclassified as stale.
- Configurable via `config.yaml` `agent.gateway_auto_continue_freshness`
  (bridged to `HERMES_AUTO_CONTINUE_FRESHNESS` at gateway startup — same
  pattern as `gateway_timeout`).  Set to 0 to disable the gate.
- `_coerce_gateway_timestamp` now explicitly rejects bool (which is a
  subclass of int and would otherwise coerce to 0.0/1.0).
- Tests rewritten to exercise the real production data shape: raw
  `history` → `_build_agent_history` strip → freshness decision.  A
  regression guard (`test_stale_tool_tail_with_production_data_shape`)
  asserts `agent_history` tool rows carry NO timestamp, protecting
  against someone "fixing" the original bug by re-adding the stripped
  field (which would break the OpenAI tool-result message contract).

Add BeliefanX to scripts/release.py AUTHOR_MAP.

E2E verified: config.yaml → env var bridge → helper returns configured
value; default 1h window; malformed/empty env var falls back to default;
ISO-Z timestamps parse; ms-epoch coerced; bool rejected.

scripts/release.py

@@ -58,6 +58,7 @@ AUTHOR_MAP = {
     "yes999zc@163.com": "yes999zc",
     "343873859@qq.com": "DrStrangerUJN",
     "uzmpsk.dilekakbas@gmail.com": "dlkakbs",
+    "beliefanx@gmail.com": "BeliefanX",
     "jefferson@heimdallstrategy.com": "Mind-Dragon",
     "steve.westerhouse@origami-analytics.com": "westers",
     "130918800+devorun@users.noreply.github.com": "devorun",