feat(compliance): add GDPR/RODO compliant cookie consent banner

Implemented cookie consent banner to comply with EU regulations (GDPR/RODO).
The banner appears on first visit and stores user preference in localStorage.

Features:
- Non-intrusive bottom banner with clear messaging
- Accept/Decline options for user choice
- Link to privacy policy in About Us page
- Responsive design for mobile and desktop
- Auto-dismisses after consent with 1s delay on first show
- High z-index to stay above all content

Also added comprehensive Privacy & Cookies section to About Us page
explaining:
- What cookies we use (essential, analytics, preferences)
- How we handle user data
- GDPR/RODO compliance statements
- Contact information for privacy questions

Changes:
- Created CookieConsent component with modern UI
- Integrated banner into App.jsx
- Updated about-us.md with privacy policy section

frontend/public/content/about-us.md

@@ -1,9 +1,33 @@
-Hi, I’m Radek – a software engineer, a West Coast Swing dancer and the person behind **spotlight.cam**. 
+Hi, I'm Radek – a software engineer, a West Coast Swing dancer and the person behind **spotlight.cam**.
 
 
-Spotlight.cam is a project built by someone who actually stands in the same registration lines, dances in the same heats and scrolls through the same event pages as you :P 
+Spotlight.cam is a project built by someone who actually stands in the same registration lines, dances in the same heats and scrolls through the same event pages as you :P
 
 
-If we ever meet at an event, I’ll probably be somewhere near the dance floor, probably pressing “record” on someone’s spotlight. 
+If we ever meet at an event, I'll probably be somewhere near the dance floor, probably pressing "record" on someone's spotlight.
 
-To be fair, the original idea for this service was actually dropped on me by a friend who was tired of hunting for someone to film her dances – I just did what any backend developer / DevOps / Linux admin would do: said “okay, that shouldn’t be that hard… right?”, opened my editor, set up a few servers and scripts… and suddenly we had a new project on our hands 😅 I also had a not-so-secret teammate: AI. Without it, this would probably still be stuck in my “one day” folder for about a year 😄 
+To be fair, the original idea for this service was actually dropped on me by a friend who was tired of hunting for someone to film her dances – I just did what any backend developer / DevOps / Linux admin would do: said "okay, that shouldn't be that hard… right?", opened my editor, set up a few servers and scripts… and suddenly we had a new project on our hands 😅 I also had a not-so-secret teammate: AI. Without it, this would probably still be stuck in my "one day" folder for about a year 😄
+
+---
+
+## Privacy & Cookies
+
+We use cookies and similar technologies to provide you with a better experience. Here's what you should know:
+
+### What cookies do we use?
+
+- **Essential cookies**: Required for authentication and core functionality (login sessions, security)
+- **Analytics**: To understand how people use the platform and improve it
+- **Preferences**: To remember your settings and preferences
+
+### Your data
+
+We respect your privacy and comply with GDPR/RODO regulations. We:
+- Only collect data necessary for the service to function
+- Never sell your personal information to third parties
+- Store your data securely
+- Allow you to delete your account and data at any time
+
+### Contact
+
+If you have any questions about privacy or cookies, feel free to reach out through our [contact page](/contact).