feat: add keyboard shortcut for theme toggle

[seffhunnn]

Summary

Added a global keyboard shortcut for instantly toggling between light and dark themes directly from the dashboard. Also updated the shortcuts modal and added aria-live announcements for improved accessibility.

Closes #230

Type of Change

• Bug fix
• New feature
• Documentation update
• Refactor / code cleanup

Changes Made

• Added global T keyboard shortcut for theme toggling
• Prevented shortcut activation while typing in inputs/textareas/contenteditable elements
• Reused existing theme toggle functionality
• Added T — Toggle theme entry to the shortcuts modal
• Added aria-live announcements for screen readers
• Added proper keyboard event cleanup handling

How to Test

Steps for the reviewer to verify this works:

1. Run the project locally using npm run dev
2. Open the dashboard page
3. Press T and verify the theme toggles instantly
4. Press T multiple times and verify the theme switches correctly
5. Focus an input or textarea and press T
6. Verify the theme does not toggle while typing
7. Press ? to open the shortcuts modal
8. Verify T — Toggle theme appears in the shortcuts list
9. Verify aria-live announcements update correctly after theme changes
10. Open browser console and verify there are no warnings or errors
11. Run npm run lint
12. Run npm run type-check

Screenshots (if UI change)

N/A

Checklist

• Linked issue in summary
• npm run lint passes locally
• No TypeScript errors (npm run type-check)
• Self-reviewed the diff
• Added/updated tests if applicable

[vercel]

@seffhunnn is attempting to deploy a commit to the PRIYANSHU DOSHI's projects Team on Vercel.

A member of the Team first needs to authorize it.

[Priyanshu-byte-coder]

1. D shortcut still active but undocumented — the handler fires on both t and d, but ShortcutsModal only shows T. Either remove d from the handler, or show both keys in the modal.

2. aria-live announcement fires on click-toggle too — the useEffect watches theme and announces on every change, including button clicks. Screen reader users clicking the toggle button hear a redundant second announcement. Scope the announcement to keyboard events only (set a ref flag in the keydown handler, read + clear it in the effect).

[seffhunnn]

Hii @Priyanshu-byte-coder i have addressed the review feedback by removing the undocumented D shortcut so only T toggles the theme now, and i also updated the aria live announcement logic so screen readers only get announcements when the theme is changed using the keyboard shortcut and not through mouse clicks.