refactor: rename Step Library → Solutions Library site-wide

User-facing text updated across page title, sidebar, command palette,
quick launch, quick actions, post-step modal, empty state, and
procedural editor. File paths/component names unchanged — those
will be renamed when the full Solutions Library feature ships.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/src/pages/StepLibraryPage.tsx

@@ -89,17 +89,17 @@ export default function StepLibraryPage() {
 
   return (
     <>
-    <PageMeta title="Step Library" />
+    <PageMeta title="Solutions Library" />
     <div className="flex h-full flex-col">
       {/* Page Header */}
       <div className="flex items-center justify-between border-b border-border px-6 py-4">
         <div className="flex items-center gap-3">
-          <span title="Step Library">
+          <span title="Solutions Library">
             <Bookmark className="h-6 w-6 text-muted-foreground" />
           </span>
           <div>
-            <h1 className="text-xl font-bold font-heading text-foreground">Step Library</h1>
-            <p className="text-sm text-muted-foreground">Reusable steps you can insert into any flow</p>
+            <h1 className="text-xl font-bold font-heading text-foreground">Solutions Library</h1>
+            <p className="text-sm text-muted-foreground">Reusable solutions from your team's troubleshooting sessions</p>
           </div>
         </div>
         {canCreateSteps && (