Improve dijkstra

[papjuli]

Implement a bidirectional Dijkstra, and use PriorityQueue.push_increase

[Copilot]

Pull Request Overview

This PR introduces a bidirectional version of Dijkstra’s algorithm, updates the UI to use it, and ensures basic testing and CI are in place.

• Implement bidirectional_dijkstra alongside updates to the existing dijkstra function.
• Swap calls in ui.rs from dijkstra to bidirectional_dijkstra.
• Add a simple GridPoint test and include tests in CI.

Reviewed Changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
src/ui.rs	Imported and invoked bidirectional_dijkstra instead of dijkstra.
src/dijkstra.rs	Added bidirectional_dijkstra, refactored dijkstra, and added timing.
src/test.rs	Added basic equality tests for GridPoint.
src/main.rs	Registered test module under cfg(test).
.github/workflows/ci.yml	Added a step to run cargo test --all in CI.

Comments suppressed due to low confidence (1)

src/test.rs:3

• The new bidirectional_dijkstra function isn’t covered by any tests. Consider adding tests that verify it returns the same path as the unidirectional version on simple graphs.

#[test]