Unify Riverflow navigation across every screen

[jonashertner]

Outcome

• uses one route order everywhere: Map, Project, Method, Sources, Law, Contribute
• adds a clear active destination and a consistent clickable Riverflow identity
• removes the ambiguous Project dialog action from primary navigation
• preserves the correct map language when returning from documentation
• keeps all destinations visible from 320 px through desktop, with a deliberate tablet layout
• adds publication checks for navigation order, active state, identity and return routes

Verification

• npm run release
• npm run check:links
• Chrome review at 1440×900, 901×700, 900×700, 768×1024, 390×844, 320×568 and 844×390
• all five languages checked at 320 px