fix(aia,ssa,asl,infra): harden SSE transport and stabilize attachment context

Deliver SSE protocol hardening for SAE/HTTP2 paths, add graceful shutdown health behavior, and improve SSA retry UX for transient stream failures. For AIA, persist attachment extraction results in database with cache read-through fallback, plus production cache safety guard to prevent memory-cache drift in multi-instance deployments; also restore ASL SR page scrolling behavior.

Made-with: Cursor

frontend-v2/src/modules/asl/components/ASLLayout.tsx

@@ -151,7 +151,7 @@ const ASLLayout = () => {
 
   return (
     <ASLLayoutContext.Provider value={contextValue}>
-      <div style={{ height: '100vh', display: 'flex', overflow: 'hidden' }}>
+      <div style={{ height: '100%', minHeight: 0, display: 'flex', overflow: 'hidden' }}>
         {/* ── 侧边栏 ── */}
         <div className="asl-sidebar">
 
@@ -277,7 +277,7 @@ const ASLLayout = () => {
         </div>
 
         {/* ── 右侧内容区 ── */}
-        <div style={{ flex: 1, overflow: 'hidden', background: '#F9FAFB' }}>
+        <div style={{ flex: 1, minWidth: 0, minHeight: 0, overflow: 'auto', background: '#F9FAFB' }}>
           <Outlet />
         </div>
       </div>