Improve CLI check path resolution and sticky agent detail tabs

Resolve relative paths in database and log checks against the config file
directory with fallback candidates. Make the AgentDetail tab bar sticky
with backdrop blur for better navigation on long pages.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

ui/src/pages/AgentDetail.tsx

@@ -363,7 +363,7 @@ export function AgentDetail() {
       {actionError && <p className="text-sm text-destructive">{actionError}</p>}
 
       <Tabs value={activeTab} onValueChange={setActiveTab}>
-        <div className="flex items-center justify-between">
+        <div className="sticky top-0 z-10 -mx-6 px-6 py-2 bg-background/90 backdrop-blur-sm flex items-center justify-between">
           <PageTabBar
             items={[
               { value: "overview", label: "Overview" },