fix(codex): relax no-byte TTFB watchdog default from 12s to 120s

The chatgpt.com/backend-api/codex endpoint can spend tens of seconds in
backend admission / prompt prefill before emitting its first SSE event. The
12s no-byte TTFB cutoff aborted those still-valid streams, surfacing as
'Codex stream produced no bytes within 12s' through all retries (Discord
reports). The OpenAI SDK's own streaming read timeout is 600s, so 12s was
~50x more aggressive than the transport layer would have tolerated.

Default the no-byte cutoff to 120s and raise the openai-codex MAX cap default
to 120s so it no longer clamps the new default back to 20s. Disabling stays
available via HERMES_CODEX_TTFB_TIMEOUT_SECONDS=0; the 25k-token auto-disable,
_STRICT override, and post-first-event idle watchdog are unchanged.

Co-authored-by: Gille <4317663+helix4u@users.noreply.github.com>

agent/chat_completion_helpers.py

@@ -284,8 +284,15 @@ def interruptible_api_call(agent, api_kwargs: dict):
     else:
         _codex_idle_timeout_default = 12.0
 
+    # No-byte TTFB cutoff. The OpenAI SDK's own streaming read timeout is far
+    # longer (openai 2.x DEFAULT_TIMEOUT.read = 600s), so a tight 12s default
+    # killed subscription-backed Codex requests mid-prefill before the backend
+    # had a chance to emit its first SSE event. Default to 120s — long enough to
+    # clear normal backend admission / prompt prefill, short enough to still
+    # reconnect promptly when the socket is genuinely wedged. Set
+    # HERMES_CODEX_TTFB_TIMEOUT_SECONDS=0 to disable this watchdog entirely.
     _ttfb_enabled = _codex_watchdog_enabled
-    _ttfb_timeout = _env_float("HERMES_CODEX_TTFB_TIMEOUT_SECONDS", 12.0)
+    _ttfb_timeout = _env_float("HERMES_CODEX_TTFB_TIMEOUT_SECONDS", 120.0)
     if _ttfb_timeout <= 0:
         _ttfb_enabled = False
     elif _openai_codex_backend:
@@ -307,7 +314,7 @@ def interruptible_api_call(agent, api_kwargs: dict):
                 _ttfb_disable_above,
             )
         else:
-            _ttfb_cap = _env_float("HERMES_CODEX_TTFB_MAX_SECONDS", 20.0)
+            _ttfb_cap = _env_float("HERMES_CODEX_TTFB_MAX_SECONDS", 120.0)
             if _ttfb_cap > 0 and _ttfb_timeout > _ttfb_cap:
                 logger.info(
                     "Capping openai-codex no-byte TTFB timeout from %.0fs to %.0fs "