Fix navigation flow and improve presentation creation workflow

## Navigation Fixes
- Fix PresentationEditor back button routing from /themes to /presentations
- Update error state back links to go to presentations list instead of themes
- Correct navigation flow: Slide Editor → Presentation Editor → Presentations List

## Workflow Improvement
- Navigate directly to slide creation (/slide/new/edit) after creating new presentation
- Streamline user flow from presentation creation to first slide authoring

This fixes the confusing navigation where back buttons were taking users to the themes page instead of the logical previous step in their workflow.

🤖 Generated with [Claude Code](https://claude.ai/code)

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

src/components/presentations/NewPresentationPage.tsx

@@ -81,8 +81,8 @@ export const NewPresentationPage: React.FC = () => {
 
       loggers.presentation.info('Presentation created successfully', { presentationId: presentation.metadata.id, name: presentation.metadata.name });
       
-      // Navigate to the new presentation editor (slide 1)
-      navigate(`/presentations/${presentation.metadata.id}/edit/slides/1`);
+      // Navigate directly to new slide creation
+      navigate(`/presentations/${presentation.metadata.id}/slide/new/edit`);
     } catch (err) {
       setError(err instanceof Error ? err.message : 'Failed to create presentation');
       loggers.presentation.error('Failed to create presentation', err instanceof Error ? err : new Error(String(err)));

src/components/presentations/PresentationEditor.tsx

@@ -115,8 +115,8 @@ export const PresentationEditor: React.FC = () => {
         <ErrorState
           title="Error Loading Presentation"
           message={error}
-          backLink="/themes"
-          backText="← Back to Themes"
+          backLink="/presentations"
+          backText="← Back to Presentations"
         />
       </div>
     );
@@ -128,8 +128,8 @@ export const PresentationEditor: React.FC = () => {
         <ErrorState
           title="Presentation Not Found"
           message="The requested presentation could not be found."
-          backLink="/themes"
-          backText="← Back to Themes"
+          backLink="/presentations"
+          backText="← Back to Presentations"
         />
       </div>
     );
@@ -142,7 +142,7 @@ export const PresentationEditor: React.FC = () => {
     <div className="presentation-editor">
       <header className="editor-header">
         <div className="presentation-info">
-          <Link to="/themes" className="back-link">← Back</Link>
+          <Link to="/presentations" className="back-link">← Back to Presentations</Link>
           <div className="presentation-title">
             <span>{presentation.metadata.name}</span>
             {presentation.metadata.description && (