feat: Enhance UI with semester-picker, CourseSettings, and color palette

[abcd1234davidchen]

This pull request introduces several improvements and feature additions to the course UI and localization system. The main highlights include updating and adding short semester names in both English and Traditional Chinese, refining course-related terminology, and enhancing the CourseScaffold widget with a new settings menu, improved palette selection workflow, and more flexible configuration options.

Localization Updates

English and Traditional Chinese Locales:

• Added short semester names (e.g., "Fall", "Spring", "上", "下") for both English and Traditional Chinese, including corresponding getters and JSON entries. [1] [2] [3] [4] [5] [6]
• Updated the translation for the main course label from "Class Schedule"/"學期課表" to "Schedule"/"課表" for clarity and consistency in both languages. [1] [2] [3] [4] [5] [6]

UI and Scaffold Enhancements

CourseScaffold and Settings:

• Replaced the palette selector button with a new menu/settings button (ApIcon.menu) that opens a comprehensive settings dialog (CourseSettings.show). This dialog allows users to change the course palette and toggle additional course display options, streamlining the user experience. [1] [2] [3]
• Refactored palette selection logic into a separate method (_applyPickedPalette) for better maintainability.
• Added support for passing a custom UI config to the semester picker via the new semesterPickerUiConfig parameter. [1] [2] [3] [4]
• Added an optional showSearchButton configuration to CourseConfig for greater flexibility.

General Improvements:

• Exported the new course_settings.dart widget for broader use.
• Minor code cleanups and improved formatting for readability and consistency. [1] [2] [3] [4]

These changes collectively enhance both the localization coverage and the configurability of the course UI, making it more user-friendly and easier to maintain.

[gemini-code-assist]

Code Review

This pull request refactors the course settings UI by replacing the settings dialog and palette picker with a new CourseSettings bottom sheet. It introduces the 'Luster' color palette (with light and dark variants), updates localization strings for shorter schedule titles and semester names, and adds support for short semester names in the SemesterPicker. Additionally, CourseScaffold now supports showSearchButton and semesterPickerUiConfig. Feedback was provided regarding an inconsistency in CourseSettings where the initialChildSize calculation logic does not match the palette selector's visibility condition.