Implement Navigation in Start your journey

[vyktoremario]

Closes: #205

[roomote]

Rooviewer Claude   See task on Roo Cloud

All issues resolved. The pagination timing fix correctly clamps page bounds within the useMemo.

• JourneyTabGrid.tsx: defaultValue does not update when filter changes, causing empty content when active tab is filtered out
• JourneyCardsDesktop.tsx: Using array indices as React keys for filtered lists may cause reconciliation issues
• JourneyCardsDesktop.tsx: Pagination reset via useEffect runs after render, causing brief flash of empty content when filtering from higher page numbers

Previous reviews

• ee4b684: Review #1
• a13e226: Review #2
• 480b4a9: Review #3
• d775f3b: Review #4
• 4533b0d: Review #5

_{Mention @roomote in a comment to request specific changes to this pull request or fix all unresolved issues.}