UX: Complete remaining page updates with user-friendly text

PLANNER MODULE:
- Ideas: 'Content Ideas' → 'Article Ideas'
- Dashboard: 'Planner Dashboard' → 'Planning Dashboard'
- Keyword Opportunities: 'Keyword Opportunities' → 'Discover Keywords'

LINKER MODULE:
- Content List: 'Link Content' → 'Add Internal Links'
- Dashboard: 'Linker Dashboard' → 'Internal Linking Dashboard'

OPTIMIZER MODULE:
- Content Selector: 'Optimize Content' → 'Improve Your Articles'
- Dashboard: 'Optimizer Dashboard' → 'Optimization Dashboard'

All page titles now use clear, action-oriented language that non-technical
users can easily understand.

frontend/src/pages/Optimizer/ContentSelector.tsx

@@ -138,11 +138,11 @@ export default function OptimizerContentSelector() {
 
   return (
     <>
-      <PageMeta title="Optimize Content" description="Select and optimize content for SEO and engagement" />
+      <PageMeta title="Improve Your Articles" description="Optimize your content for better SEO and engagement" />
       
       <div className="space-y-6">
         <PageHeader
-          title="Optimize Content"
+          title="Improve Your Articles"
           lastUpdated={new Date()}
           badge={{
             icon: <BoltIcon />,

frontend/src/pages/Optimizer/Dashboard.tsx

@@ -66,12 +66,12 @@ export default function OptimizerDashboard() {
 
   return (
     <>
-      <PageMeta title="Optimizer Dashboard" description="Content optimization overview and statistics" />
+      <PageMeta title="Optimization Dashboard" description="Track your content optimization progress" />
       
       <div className="space-y-6">
         <div className="flex items-center justify-between mb-6">
           <PageHeader
-            title="Optimizer Dashboard"
+            title="Optimization Dashboard"
             lastUpdated={new Date()}
             badge={{
               icon: <BoltIcon />,