fix(brain): ride out transient Claude 529 overloads

A single Claude 529 Overloaded dropped the voice turn straight to the apology
fallback. The anthropic SDK retries >=500/429 but only twice by default, which
a busy window can outlast. Raise max_retries (WSAI_BRAIN_MAX_RETRIES, default 4)
so transient overloads recover silently, and give overloads their own spoken
fallback ("서버가 붐벼서...") distinct from generic failures. Kept modest so a
sustained outage still fails fast instead of leaving the bot silent.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

wsai/backends/claude.py

@@ -29,6 +29,13 @@ from ..interfaces import Frame, Reply, ScreenObservation
 # this identity string; the real persona/instructions go in later blocks.
 _CLAUDE_CODE_ID = "You are Claude Code, Anthropic's official CLI for Claude."
 
+# Claude occasionally returns 529 Overloaded; the anthropic SDK retries >=500
+# (and 429) with exponential backoff, but its default of 2 tries can be too few
+# to ride out a busy window. Bump it so a transient overload doesn't drop the
+# voice turn to the apology fallback. Kept modest so a *sustained* overload
+# still fails fast rather than leaving the bot silent for many seconds.
+_MAX_RETRIES = int(os.environ.get("WSAI_BRAIN_MAX_RETRIES", "4"))
+
 
 def _load_oauth_token() -> str | None:
     path = os.environ.get("CLAUDE_CREDENTIALS_PATH")
@@ -59,7 +66,7 @@ class _Auth:
         key = self._explicit_key or os.environ.get("ANTHROPIC_API_KEY")
         if key:
             if self._client is None:
-                self._client = self._anthropic.AsyncAnthropic(api_key=key)
+                self._client = self._anthropic.AsyncAnthropic(api_key=key, max_retries=_MAX_RETRIES)
             self._oauth = False
             return self._client
         tok = _load_oauth_token()
@@ -70,7 +77,7 @@ class _Auth:
             )
         if tok != self._token:
             self._token = tok
-            self._client = self._anthropic.AsyncAnthropic(auth_token=tok)
+            self._client = self._anthropic.AsyncAnthropic(auth_token=tok, max_retries=_MAX_RETRIES)
         self._oauth = True
         return self._client