Replace manual turn-by-turn instruction generation

[LourenzBani]

Problem

Turn-by-turn instructions are generated through custom distance and direction calculations rather than using navigation-native guidance data.

Current Behavior

• Route geometry is retrieved from mapping APIs.
• Instructions are manually constructed in application code.
• Navigation updates are difficult to modify dynamically.

Expected Behavior

• Use routing API navigation instructions directly where possible.
• Support dynamic rerouting and route updates.
• Reduce maintenance complexity.