feat: RichText component for safe PocketBase HTML rendering

Add html-react-parser-backed RichText component that converts HTML
strings from PocketBase rich-text fields into React elements without
dangerouslySetInnerHTML. Replace raw <p> render in IntroSection and
BioSection, and drop the invalid slug filters those collections lacked.

src/shared/ui/index.ts

@@ -6,7 +6,7 @@ export type { CardBackground } from './Card';
 export { Card, CardContent, CardDescription, CardFooter, CardHeader, CardTitle } from './Card';
 
 export { Input, Textarea } from './Input';
+export { RichText } from './RichText';
 export type { ContainerSize, SectionBackground } from './Section';
 export { Container, Section } from './Section';
-
 export { TechStackBrick, TechStackGrid } from './TechStack';