refactor: install tailwind and restyle most components

[ajaygandecha]

This PR installs Tailwind v4 and ports all main features and widgets to use Tailwind styling. All pages retain the same styling as before, with some enhancements to certain pages. The switch to Tailwind should significantly improve DX for future development, reduces the clutter and allows the removal of numerous .css files, removes many style classes that were defined but never used, and also reduce the CSS bundle size shipped to the client side.

Other Notes:

• The <mat-pane> component will soon be marked as deprecated, as the nesting added ends up causing unfortunate effects on styling (often remedied only with ::ng-deep, which is also now deprecated and bad practice). The pane effect can be created with <mat-card appearance="outlined" class="border-transparent!">. We may be able to make pane a directive in the future added to cards like so: <mat-card pane>.
• Some components in shared and the signage feature have not been ported to Tailwind yet.
• This PR attempts to add a tailwind linter.
• Future work can be done to port over some of the manual styles added in styles.scss to be custom Tailwind styles.

This PR resolves #819

[ajaygandecha]

Note to self: Explore the use of canonical classes in Tailwind for M3 variables (like bg-(--mat-primary))