feat: add optional Codex warm-up scheduler

.env.example

@@ -36,6 +36,21 @@ STATUS_CHANNEL_ID=                    # Discord channel ID for live status updat
 # STATUS_SHOW_ROOMS=true              # Show room status in dashboard
 # STATUS_SHOW_ROOM_DETAILS=false      # Show detailed room info
 
+# --- Codex warm-up (optional, disabled by default) ---
+# Sends a tiny real Codex prompt to near-zero-usage accounts so their reset
+# countdown starts after a fresh quota window. Keep disabled if OpenAI changes
+# policy or starts blocking automated warm-up prompts.
+# CODEX_WARMUP_ENABLED=false
+# CODEX_WARMUP_PROMPT=Reply exactly OK. Do not run tools.
+# CODEX_WARMUP_MODEL=                 # Defaults to CODEX_MODEL
+# CODEX_WARMUP_INTERVAL_MS=300000     # Check every 5min
+# CODEX_WARMUP_MIN_INTERVAL_MS=18300000  # Per-account minimum gap: 5h5m
+# CODEX_WARMUP_STAGGER_MS=1800000     # Global gap between accounts: 30min
+# CODEX_WARMUP_MAX_USAGE_PCT=0        # Only warm accounts at/below this 5h usage
+# CODEX_WARMUP_MAX_D7_USAGE_PCT=99    # Skip weekly-exhausted accounts
+# CODEX_WARMUP_MAX_CONSECUTIVE_FAILURES=2
+# CODEX_WARMUP_FAILURE_COOLDOWN_MS=21600000  # Back off 6h after repeated failure
+
 # --- Fallback provider (when Claude/Codex both unavailable) ---
 # FALLBACK_ENABLED=true               # Enable fallback provider
 # FALLBACK_PROVIDER_NAME=kimi         # Provider name for logging