[Feature]: Add a proper 404 / Not Found page

[RounakKumarAgarwal]

Problem Statement

The app currently renders a bare, unstyled placeholder for unmatched routes. In src/routes/__root.tsx, the root route's notFoundComponent is:

notFoundComponent: () => <div>Not Found</div>,

Navigating to any unknown route (e.g. /some-missing-page) shows plain "Not Found" text with no styling and no way back into the app. It looks broken and is inconsistent with the rest of the UI.

Proposed Solution

Replace the placeholder with a styled 404 page that:

• Uses the existing DaisyUI + Tailwind design tokens (bg-base-200, text-base-content, btn btn-primary, etc.) so it respects the current light/dark theme
• Provides a clear "back to app" action linking to /trackpad
• Routes its text through the existing i18n helper (t(...)) instead of hardcoding strings

The errorComponent right next to it is a similar bare stub (Error: {message}); happy to polish that in the same PR if maintainers want, or keep this scoped to the 404 only.

Alternatives Considered (Optional)

Leaving the default placeholder as-is — rejected since it reads as a broken page and doesn't match the app's design.

Additional Context (Optional)

Picked this up from a team meeting where the maintainers asked me to take it on. Opening this to track it; PR to follow.

Checklist

• I have searched for existing feature requests to avoid duplicates

[RounakKumarAgarwal]

@PinJinx Please assign it to me