Set shuttle link and visibility from an external config file

[a6wu]

## Summary

Updates the Shuttle card’s external transit map action to come from a config file, allowing the button label, destination, and visibility to be configured external to the app.


## Changelog

[General] [Change] - Configure the Shuttle card external link button from the cards list response and hide it when no external URL is provided.


## Test Plan

- Verified `CardsModel` parses optional `externalLinkURL` and `externalLinkText` fields with empty-string defaults.
- Verified Shuttle card no longer uses the hardcoded Wayfinder URL.
- Verified the external link button is only rendered when `externalLinkURL.trim()` is non-empty.
- Ran targeted Flutter analysis on the updated model and Shuttle card files.

[Copilot]

Pull request overview

This PR makes the Shuttle card’s external “transit map” action configurable via the cards list response (URL, label, and visibility), removing the previously hardcoded Wayfinder link.

Changes:

• Add externalLinkURL / externalLinkText to CardsModel (JSON parse + serialization) with empty-string defaults.
• Update the Shuttle card to render an external-link ActionButton only when a non-empty external URL is provided by config.
• Miscellaneous formatting and minor accessibility improvements (notably in Dining detail buttons’ semantics).

Reviewed changes

Copilot reviewed 17 out of 17 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
lib/ui/shuttle/shuttle_card.dart	Uses card config (externalLinkURL / externalLinkText) to control Shuttle external-link button and visibility.
lib/core/models/cards.dart	Extends cards config model to include external link URL/text fields.
lib/ui/dining/dining_detail_view.dart	Adds Semantics wrappers for “Get Directions” / “Visit Website” / “View Menu” buttons.
lib/ui/news/news_list.dart	Formatting only.
lib/ui/navigator/bottom.dart	Formatting only.
lib/ui/home/home.dart	Formatting only.
lib/ui/dining/dining_list.dart	Formatting only.
lib/ui/availability/availability_display.dart	Formatting only.
lib/ui/availability/availability_card.dart	Formatting only (multiline if).
lib/ui/ai_assistant/citation_web_view.dart	Formatting only.
lib/ui/ai_assistant/chat_message_bubble.dart	Formatting only.
lib/core/services/tgpt_services/chat_stream.dart	Formatting only.
lib/core/providers/chat_provider.dart	Formatting only.
lib/core/providers/availability.dart	Formatting only.
lib/core/models/tgpt_models/chat_response.dart	Formatting only.
lib/core/models/tgpt_models/chat_message_persistent.g.dart	Formatting only.
lib/app_constants.dart	Formatting only.

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[angelawu236]

It might be worth it to revert back to the old code for the files that aren't related to the shuttle, in case it's introducing any new bugs because of formatting. Also, maybe testing with an invalid/non existing link from the env could also be done, so in case in the future if the config doesn't have a valid link, the app still looks/works fine.

[hamedhemmati]

Looks good