refactor(service): use parsed bus route lines instead of raw patterns; feat(api): serve these parsed lines

[jumpy-cat]

Description

Move the majority of bus route line processing into the backend so that more information in available during journey planning. Old routes kept for backwards compatibility. Add regression tests for the summer bug and something else that was enccountered.

Type of Change

• New feature (feat)
• Bug fix (fix)
• Refactor / code improvement
• Dependency / build update
• Documentation
• Other (explain)

Related Issues

Part of the backend side for mbusdev/bluebus-flutter#98

Changes Made

• Flutter: n/a
• Backend (TypeScript):
  • new api/v4/ router for backwards incompatible changes
    • contains new getAllMbusRoutes and getAllRideRoutes
  • Patterns are now being processed into BusRouteLines similar to those used in the frontend (but missing a few fields)
  • existing usages of routes / ride routes refactored to use processed bus route lines, also reduced the amount of nesting using flatten/flatMap
  • new test file: tries detours and routes of differing lengths to recreate the previous bug, confirms that detours & routes are both correclty passed through
  • renamed from bustimeTypes to bustimeCommon because it also contains logic now
• Firebase / Shared: n/a

Testing Done

Flutter:

• Tested on:
  • iOS Simulator
  • Android Emulator (checked if routes still show up, see the corresponding FE issue)
  • Physical device

Screenshots / Demo (if UI or notification change)

Checklist

• Commit messages follow Conventional Commits
• PR title follows [type](scope): short description
• PR target branch is not main and is our current working update branch (e.g. maizebus2.1)
• No print() / debugPrint() / console.log() left in production code
• Secrets / keys not committed