Overhaul Mapping and Routing System

[austinkden]

This submission overhauls the core mapping and routing infrastructure of the application.

Key changes include:

1. Data Model (mapping.json): Transitioned to a structured node system (intersections vs. waypoints) and added rich edge data for geometry and directionality.
2. Pathfinding (script.js): Enhanced the Dijkstra implementation to handle one-way systems, crucial for the newly modeled highways and ramps.
3. Rendering: The map now accurately reflects road curves by drawing polylines through intermediate waypoints. The system intelligently reverses waypoint sequences when traversing undirected edges in reverse.
4. Navigation: Turn-by-turn directions are now more concise, focusing on real intersections and filtering out internal geometry points.

Verification was performed using automated JSON validation, Playwright E2E tests, and visual inspection of generated route screenshots confirming correct one-way flow and curved geometry.

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PR created automatically by Jules for task 6434123903747559881 started by @austinkden

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[austinkden]

@jules Actually... tomorrow I'm going to manually add a lot of data. I will be adding several nodes per road (one for each lane) and several nodes per intersection (for each lane and direction)
Hopefully this will make it easier... please make sure all the code will work for this. Don't worry about clearing mapping.json - i'll handle that tomorrow

[google-labs-jules]

@jules Actually... tomorrow I'm going to manually add a lot of data. I will be adding several nodes per road (one for each lane) and several nodes per intersection (for each lane and direction)
Hopefully this will make it easier... please make sure all the code will work for this. Don't worry about clearing mapping.json - i'll handle that tomorrow

@jules Acknowledged. I have updated the routing logic in script.js to be more robust for high-density data. Specifically:

1. POIs (buildings) can now dynamically connect to any non-POI nodes (like lane-specific nodes or waypoints), ensuring they find the nearest entry/exit point regardless of whether it's a major intersection.
2. The directions engine has been refined to correctly handle paths that might start with several waypoint segments, ensuring the 'Head towards' instruction identifies the first relevant landmark.

The code is ready for the new data!