Improve settings readability, fix theme sync bugs, and enhance timer interactions

[Fideow2]

Hi @RoderickQiu,

Thank you for maintaining wnr🤓🤓🤓 — I've been using it daily and really appreciate its clean design and focus-friendly philosophy!😍😍😍

While using it, I noticed a few UI/UX friction points and theme synchronization issues that I thought I could help improve.🤔🤔🤔 This PR bundles several small but meaningful fixes and enhancements that should make the app feel more polished without changing its core character.🥹🥹🥹

Changes

Bug Fixes

• Fix theme color sync for main interface text: Custom theme colors previously caused the main interface text to revert to default colors unexpectedly. Now text colors properly persist with the selected theme.
• Fix theme color sync for statistics page: The "Usage Statistics" page and its charts did not reflect custom theme colors. Colors now synchronize correctly across all UI components.
• Fix button hit area alignment: Main interface button touch targets were misaligned with their visible text labels, making them difficult to interact with. Hit areas now properly match the visual elements.
• Fix mini mode access after timer completion: In simple timer mode, the mini mode entry remained clickable after the timer finished, causing unexpected behavior. The mini mode entry is now properly disabled when the timer completes.

UI/UX Improvements

• Collapse verbose setting descriptions: Lengthy feature descriptions in settings were visually overwhelming. Added a collapsible "?" button that expands to show detailed explanations on demand.
• Adjust settings typography hierarchy: Text sizes in settings were inconsistently scaled and difficult to scan. Restructured font sizing to follow clear visual hierarchy.
• Relocate back button to top-left: The back button was positioned counter-intuitively. Moved it to the top-left corner for more natural navigation flow.
• Center pause button in mini mode: The pause button in mini mode was off-center. Centered it for better visual balance.
• Rename "Skip" to "Reset" in stopwatch mode: The "Skip" label in stopwatch mode was semantically misleading since the action resets the timer rather than skipping a phase. Renamed to "Reset" for clarity.

Testing

• Verified theme color persistence across app restarts
• Confirmed statistics page reflects custom colors correctly
• Tested collapsible descriptions on various screen sizes
• Validated button hit areas on touch and mouse interactions
• Confirmed mini mode is inaccessible after timer completion in simple mode

Each change is in its own commit, so feel free to cherry-pick or comment on individual ones if anything needs adjustment.😘😘😘 I'm happy to iterate based on your feedback!🫡🫡🫡

Best regards ❤️❤️❤️

[RoderickQiu]

Hi, thanks for your contributions. Some changes are unwanted, so I reverted in one single commit (e.g. those that are inappropriate when you are on macOS, since this is a cross-platform app; and some edge cases caused by universal style changes). Other changes are warmly welcomed.