fix(gateway): config.yaml path for WhatsApp/Weixin text-batch delays

Convert the salvaged text-debounce delays from HERMES_* env vars to
config.yaml (gateway.platforms.<name>.extra.text_batch_delay_seconds /
text_batch_split_delay_seconds), per the '.env is for secrets only'
policy. Adds a finite/non-negative guard so bad YAML values fall back to
the defaults instead of crashing asyncio.sleep().

- whatsapp.py / weixin.py: read delays via _coerce_float_extra(config.extra)
- update Weixin content-dedup regression test for the deferred dispatch path
- add text-debounce coverage (whatsapp + weixin): defaults, config override,
  bad-value fallback, env-var-ignored, burst-collapse, lone-message
- docs: WhatsApp + Weixin config keys

gateway/platforms/weixin.py

@@ -1184,9 +1184,16 @@ class WeixinAdapter(BasePlatformAdapter):
         # iLink delivers messages individually, so rapid multi-message
         # bursts (forwarded batches, paste-splits) each trigger a
         # separate agent invocation.  Default 3s delay / 5s split delay
-        # are tuned for iLink's typical delivery cadence.
-        self._text_batch_delay_seconds = float(os.getenv("HERMES_WEIXIN_TEXT_BATCH_DELAY_SECONDS", "3.0"))
-        self._text_batch_split_delay_seconds = float(os.getenv("HERMES_WEIXIN_TEXT_BATCH_SPLIT_DELAY_SECONDS", "5.0"))
+        # are tuned for iLink's typical delivery cadence.  Tunable via
+        # config.yaml under
+        # ``gateway.platforms.weixin.extra.text_batch_delay_seconds`` /
+        # ``text_batch_split_delay_seconds``.
+        self._text_batch_delay_seconds = self._coerce_float_extra(
+            "text_batch_delay_seconds", 3.0
+        )
+        self._text_batch_split_delay_seconds = self._coerce_float_extra(
+            "text_batch_split_delay_seconds", 5.0
+        )
         self._pending_text_batches: Dict[str, MessageEvent] = {}
         self._pending_text_batch_tasks: Dict[str, asyncio.Task] = {}
 
@@ -1196,6 +1203,25 @@ class WeixinAdapter(BasePlatformAdapter):
                 self._token = str(persisted.get("token") or "").strip()
                 self._base_url = str(persisted.get("base_url") or self._base_url).strip().rstrip("/")
 
+    def _coerce_float_extra(self, key: str, default: float) -> float:
+        """Read a float from ``config.extra``, guarding against bad/non-finite values.
+
+        The result is fed directly to ``asyncio.sleep()``, so NaN/Inf and
+        unparseable values fall back to ``default``.
+        """
+        import math
+
+        value = self.config.extra.get(key) if getattr(self.config, "extra", None) else None
+        if value is None:
+            return float(default)
+        try:
+            parsed = float(value)
+        except (TypeError, ValueError):
+            return float(default)
+        if not math.isfinite(parsed) or parsed < 0:
+            return float(default)
+        return parsed
+
     @staticmethod
     def _coerce_list(value: Any) -> List[str]:
         if value is None:

gateway/platforms/whatsapp.py

@@ -284,11 +284,37 @@ class WhatsAppAdapter(BasePlatformAdapter):
         # message triggers a separate agent invocation, wasting tokens and
         # flooding the user with reply fragments.  Default 5s delay /
         # 10s split delay are conservative for WhatsApp's delivery cadence.
-        self._text_batch_delay_seconds = float(os.getenv("HERMES_WHATSAPP_TEXT_BATCH_DELAY_SECONDS", "5.0"))
-        self._text_batch_split_delay_seconds = float(os.getenv("HERMES_WHATSAPP_TEXT_BATCH_SPLIT_DELAY_SECONDS", "10.0"))
+        # Tunable via config.yaml under
+        # ``gateway.platforms.whatsapp.extra.text_batch_delay_seconds`` /
+        # ``text_batch_split_delay_seconds``.
+        self._text_batch_delay_seconds = self._coerce_float_extra(
+            "text_batch_delay_seconds", 5.0
+        )
+        self._text_batch_split_delay_seconds = self._coerce_float_extra(
+            "text_batch_split_delay_seconds", 10.0
+        )
         self._pending_text_batches: Dict[str, MessageEvent] = {}
         self._pending_text_batch_tasks: Dict[str, asyncio.Task] = {}
 
+    def _coerce_float_extra(self, key: str, default: float) -> float:
+        """Read a float from ``config.extra``, guarding against bad/non-finite values.
+
+        The result is fed directly to ``asyncio.sleep()``, so NaN/Inf and
+        unparseable values fall back to ``default``.
+        """
+        import math
+
+        value = self.config.extra.get(key) if getattr(self.config, "extra", None) else None
+        if value is None:
+            return float(default)
+        try:
+            parsed = float(value)
+        except (TypeError, ValueError):
+            return float(default)
+        if not math.isfinite(parsed) or parsed < 0:
+            return float(default)
+        return parsed
+
     def _effective_reply_prefix(self) -> str:
         """Return the prefix the Node bridge will add in self-chat mode."""
         whatsapp_mode = os.getenv("WHATSAPP_MODE", "self-chat")