# Navigation Simulation & Fixes

## Problem
The user reported "LA NAVIGATION EST TOUJOURS FAUSSE !" (Navigation is still false/wrong).
This was identified as a lack of realistic movement simulation when testing the "Navigation" mode. The map would stay static while the speed indicator fluctuated randomly, and instructions would not update.

## Solution
We implemented a robust simulation engine within `MapPage.mobile.vue` that:
1.  **Simulates Movement**: Moves the user location along the actual route segments (geometry) instead of just updating a speed number.
2.  **Abstracts Position**: Created `displayedPosition` computed property that seamlessly switches between real GPS `currentPosition` and `simulatedPosition`.
3.  **Reactive Components**: Updated all dependent components to use `displayedPosition`:
    *   `MapView`: The blue dot now moves along the road.
    *   `useNavigationGuidance`: Turn-by-turn instructions now update as the simulated position advances.
    *   `useStageAutoCompletion`: Stages are automatically marked as visited when the simulated position reaches them.
    *   `LiveParticipantsList`: Shows the simulated position to the user.
4.  **User Control**: Added a "SIM" badge in the top bar when simulation is active, allowing the user to stop it. Added a "NO GPS" badge to start simulation if no signal is found.

## Key Changes
- **File**: `apps/web/src/modules/map/pages/MapPage.mobile.vue`
- **New Logic**: `startSimulation()`, `stopSimulation()`, `displayedPosition`.
- **Updated Dependencies**: `useNavigationGuidance`, `useStageAutoCompletion`, `MapView`.

## Verification
1.  Open the app in Mobile view.
2.  Select "Navigation" mode.
3.  If no GPS signal is found (or in Dev mode), simulation should auto-start (or click "NO GPS").
4.  Observe the blue dot moving along the route.
5.  Observe instructions updating (e.g. "Turn right in 50m").
6.  Observe speed updating realistically.
