feat(layout): add tamil99 layout (@ving-sh)

[ving-sh]

Description

Checks

• Adding/modifying Typescript code?
  • I have used qs, qsa or qsr instead of JQuery selectors.
• Adding quotes?
  • Make sure to include translations for the quotes in the description (or another comment) so we can verify their content.
• Adding a language?
  • Make sure to follow the languages documentation
  • Add language to packages/schemas/src/languages.ts
  • Add language to exactly one group in frontend/src/ts/constants/languages.ts
  • Add language json file to frontend/static/languages
• Adding a theme?
  • Make sure to follow the themes documentation
  • Add theme to packages/schemas/src/themes.ts
  • Add theme to frontend/src/ts/constants/themes.ts
  • Add theme css file to frontend/static/themes
  • Add some screenshots of the theme, especially with different test settings (colorful, flip colors) to your pull request
• Adding a layout?
  • Make sure to follow the layouts documentation
  • Add layout to packages/schemas/src/layouts.ts
  • Add layout json file to frontend/static/layouts
• Adding a font?
  • Make sure to follow the themes documentation
  • Add font file to frontend/static/webfonts
  • Add font to packages/schemas/src/fonts.ts
  • Add font to frontend/src/ts/constants/fonts.ts
• Make sure the PR title follows the Conventional Commits standard. (https://www.conventionalcommits.org for more info)
• Check if any open issues are related to this PR; if so, be sure to tag them below.
• Make sure to include your GitHub username prefixed with @ inside parentheses at the end of the PR title.

Closes #

Discussion #6483

Layout Documentation
https://learn.microsoft.com/en-us/globalization/keyboards/kbdtam99
http://kbdlayout.info/KBDTAM99?arrangement=ANSI104

[github-actions]

Continuous integration check(s) failed. Please review the failing check's logs and make the necessary changes.

[ving-sh]

Keymap not working properly for tamil99

tried this layout in local/dev, input works fine. but in keymap mode is not working as expected,

• if I have to type க், I have to press h+f, so i press h it correctly highlights க/or letter h -> next i have to press f for ் but the highlight is not moving to f for letter ் on the layout it still stays h/க.
• if I have to type கா i have to press h+q, i correctly highlights h / க then the highlight has to move to ஆ/q but it just stays in ஆ/q

How can I fix this. I don't find how the keymap function works or where to fix. I assume it is layout independent and mapped based on the expected next input...
Would appreciate a guidance or a help to fix this key map mode highlight issue.

i see key map working fine for hindi inscript layout , tamil99 also needs something like this..

[github-actions]

Continuous integration check(s) failed. Please review the failing check's logs and make the necessary changes.