fix: deeplink backtracking

[eames-palmer]

Revision 1 Changes

1. Switched to Flutter Deeplink handling.
2. Set launch mode to standard and un-nest item routing.
3. Add back button to items opened by deeplink.

Why

• 1.1: Existing app_links was unnecessary dependency for the complexity of Hacki's link handling.
• 1.2: Prevents duplicate back-stack entries when opening articles through deep links.
• 1.3: Back buttons were not present in the upper left corner after swapping to this new behavior.

Testing

• Built the .apk and tested deeplink backtracking alongside regression testing for existing item handling.
• Tested on Android 17 with Build Android APK Workflow

Related Links

1. Addresses Go back to previous app #743.
2. https://developer.android.com/guide/topics/manifest/activity-element#lmode

[Livinglist]

Mad love! Taking a look after I get home.