Implemented a comprehensive UI tour in ui-tour.js with multilingual support, guiding users through key functionalities and settings.

Included localized messages for Chinese (Traditional and Simplified) and English.

Enhance UI and functionality of the word management interface

Updated styles in ui-toast.js for improved visual feedback on toast notifications.

Refined layout and design in words.html, including responsive adjustments and new color schemes.

Added new buttons and controls for better user interaction, including a practice mode button.

Improved search and sorting functionalities in words.js, with enhanced rendering logic for search results.

Implemented animations for UI elements to enhance user experience during interactions.

Updated word count display and tooltip formatting for clarity.

Enhanced delete and toggle learned functionalities with visual feedback.

Cross-browser packaging and Firefox readiness
Added dedicated Chrome/Firefox manifests and build flow.
Improved Firefox compatibility handling and policy-related manifest updates.
Much broader language support
Expanded source-language options significantly (including Arabic, Bengali, Turkish, Thai, Urdu, Brazilian Portuguese, Tamil, Telugu, Swahili, and more).
Improved language labeling in settings with “English name + native script” for faster recognition.
Full UI internationalization pass
UI language coverage was extended and normalized across popup, fullscreen, settings, and modal flows.
Added fallback logic to avoid broken strings when a translation key is missing.
Localized many previously hardcoded texts (examples, dictionary states, dialogs, status messages).
Auto-save settings
Settings now save immediately on change (no manual Save dependency).
Includes debounce-based persistence for smoother UX.
Reduces user errors from forgetting to save.
Translation behavior improvements
Added language-detection-based skip logic so selected text in the user’s own UI language is not redundantly translated.
Chinese variant handling was improved (Traditional/Simplified treated as same-language bucket where appropriate).
Dictionary system maturity
Dictionary lookup routing was refined by language/provider.
Better handling for unsupported/slow/error cases.
Add Word flow improved with dictionary candidates, apply actions, and better fallback behavior.
Example sentence system evolution
Stronger filtering and deduplication rules.
Better handling of noisy web payload text and low-information snippets.
Added user controls (pin/remove), tighter limits, and improved display.
New frequency model: DF-TF style stats
Replaced simple “count by examples only” perception with two metrics:
DF: number of distinct pages where the word contributed new examples
TF: total encounters (new examples accumulated)
Display format changed to DF-TF (e.g., 3-10).
Frequency sorting now prioritizes DF first, then TF.
Search and fullscreen usability upgrades
More prominent search UI.
Debounced search to reduce excessive queries and improve responsiveness.
Improved dictionary result rendering in fullscreen view.
Stability and robustness improvements

auto-collect example sentences while browsing