feat(agent99): bridge sre alerts to windows relay

apps/api/src/core/config.py

@@ -925,6 +925,28 @@ class Settings(BaseSettings):
         default="",
         description="Telegram Webhook Secret Token（setWebhook 設定的同一值）",
     )
+    AGENT99_SRE_ALERT_INBOX_PATH: str = Field(
+        default="",
+        description=(
+            "Optional mounted path for Agent99 SRE alert inbox. Empty disables the "
+            "fail-open Alertmanager to Agent99 file bridge."
+        ),
+    )
+    AGENT99_SRE_ALERT_RELAY_URL: str = Field(
+        default="",
+        description=(
+            "Optional Agent99 SRE alert relay endpoint. When set, Alertmanager "
+            "events are posted to Agent99 before falling back to the mounted file inbox."
+        ),
+    )
+    AGENT99_SRE_ALERT_RELAY_TOKEN: str = Field(
+        default="",
+        description="Optional shared token for Agent99 SRE alert relay POSTs.",
+    )
+    AGENT99_SRE_ALERT_RELAY_TIMEOUT_SECONDS: float = Field(
+        default=3.0,
+        description="Timeout for fail-open Agent99 SRE alert relay POSTs.",
+    )
     # 2026-04-24 Claude Sonnet 4.6 (ADR-095 WS4): Hermes NL 自然語言閘道
     # false=不啟用（預設），true=啟用 @mention 問答（需 ANTHROPIC_API_KEY）
     HERMES_NL_ENABLED: bool = Field(