Design: improve stop arrival page for stops with multiple platforms or directions

[github-world192]

Problem

Many stop names map to multiple representative stop IDs/platforms. The UI currently presents arrivals as if one station name has one unified stop surface, which can hide routes or make arrivals feel inconsistent.

Product design direction

Introduce a clear platform/direction model in the stop arrival experience:

• Show the selected stop name prominently.
• If multiple platforms/directions exist, expose a segmented control or compact tabs.
• Label each group with useful human language, such as direction, destination, or platform context.
• Preserve a combined view only if it clearly communicates that results are merged.

Acceptance criteria

• Stops with multiple representative IDs do not silently show only one platform's arrivals.
• Users can understand which direction/platform each arrival belongs to.
• The default view is still fast to scan for single-platform stops.
• Arrival rows remain stable during refresh and do not jump unnecessarily.
• Empty states explain whether no buses exist or only one platform has no data.

Senior design advice

Transit riders are often making decisions under time pressure. Direction ambiguity is more damaging than visual clutter, so prefer a slightly denser but explicit structure over a simplified view that hides context.