### Describe Your Changes
### Pull Request Description:
1. **HTML File Structure Optimization**: Adjusted the location of HTML
files for different builds to prevent redundant files in the final
output. See issue #6900
2. **Metadata Fixes**: Corrected metadata in HTML files for each build
configuration.
3. **Favicon Update**: Replaced PNG favicon (`14 KB` and `1.58 KB`) with
SVG (`1.35 KB`).
4. **Social Media Optimization**: Optimized the social preview image,
reducing its size by `60.2 KB`.
5. **Git Ignore Update**: Added `public/index.html` to `.gitignore` as
it is dynamically generated during the build process.
### Checklist
The following checks are **mandatory**:
- [x] My change adheres [VictoriaMetrics contributing
guidelines](https://docs.victoriametrics.com/contributing/).
* feat: replace @codemirror to text field
* feat: switch to Preact from React
* fix: optimize mui imports
* fix: remove unused vars
* update package-lock.json
* app/vmselect/vmui: `make vmui-update`
Co-authored-by: Aliaksandr Valialkin <valyala@victoriametrics.com>
