feat: SEO improvements, OG image endpoint, favicon, and metadata (#104)

- Add dynamic OG image generation endpoint (/og) adapted from monorepo
- Replace favicon with monorepo version, remove unused icon.svg
- Add seo.ts config, robots.ts, sitemap.ts for better search indexing
- Add per-page metadata (editor, viewer, settings, profile, community)
- Remove stale package-lock.json that caused ENOWORKSPACES errors with Next.js
- Add OG fonts (Geist Regular, Plus Jakarta Sans SemiBold)

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

apps/editor/components/ui/sidebar/icon-rail.tsx

@@ -36,7 +36,7 @@ export function IconRail({
         className,
       )}
     >
-      {/* Pascal Logo - Link to Hub */}
+      {/* Pascal logo - link to the home page */}
       <Tooltip>
         <TooltipTrigger asChild>
           <Link
@@ -52,7 +52,7 @@ export function IconRail({
             />
           </Link>
         </TooltipTrigger>
-        <TooltipContent side="right">Back to Hub</TooltipContent>
+        <TooltipContent side="right">Back to Pascal Editor</TooltipContent>
       </Tooltip>
 
       {/* Divider */}