feat: sort map visualization stops by sequence number instead of name

[aminamos]

Summary:

Resolves #123.
Sorts transit stops by stop_sequence in the GTFS route map visualization instead of alphabetical order, ensuring route paths trace their actual transit path.

Expected behavior:

Stops in the route detail drawer and map trace in chronological service sequence order.

Testing tips:

1. Checkout feat/123-sort-stops-by-sequence.
2. Run yarn test.
3. Open a route visualization on /feeds/gtfs/mdb-100/map.

Please make sure these boxes are checked before submitting your pull request - thanks!

• Run the unit tests with yarn test to make sure you didn't break anything
• Add or update any needed documentation to the repo
• Format the title like "feat: [new feature short description]". Title must follow the Conventional Commit Specification(https://www.conventionalcommits.org/en/v1.0.0/).
• Linked all relevant issues
• Include screenshot(s) showing how this pull request works and fixes the issue(s)

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