refactor(header): modernize header styles and remove unused module

Update header component UI and streamline imports.

- Remove MatToolbarModule import and module list entry
  because the toolbar styling is handled by local SCSS and the
  Angular Material toolbar is no longer required.
- Rewrite header SCSS to introduce a .modern-header wrapper with
  consistent sizing, padding, alignment and a subtle bottom border.
- Add layered ambient and depth effects: refined ::before ambient
  gradient (headerAmbience), ::after bottom accent, and adjusted
  keyframes for a gentler motion.
- Refine home-header styles to target .modern-header and tune colors
  and gradients for a cohesive dark theme.
- Rework .brand-block visuals: lighter glass effect, adjusted
  radii, blur, borders, hover transform, and shadowing for a modern
  elevated look.
- Minor cleanup: remove legacy variables and comments; improve
  box-sizing, layout, and pointer-event handling to ensure expected
  interaction regions.

These changes modernize the header's visual design, improve layout
consistency across pages, and remove an unnecessary module import.

apps/web/src/app/app.component.ts

@@ -1,4 +1,4 @@
-import { Component, inject, OnInit } from '@angular/core';
+import { Component, HostBinding, inject, OnInit } from '@angular/core';
 import { MatDialog } from '@angular/material/dialog';
 import { Router, RouterOutlet } from '@angular/router';
 import { Actions, ofType } from '@ngrx/effects';
@@ -27,6 +27,9 @@ import { SearchResultsComponent } from './xtream-tauri/search-results/search-res
     imports: [RouterOutlet],
 })
 export class AppComponent implements OnInit {
+    @HostBinding('class.macos-platform') get isMacOS() {
+        return window.electron && navigator.platform.toLowerCase().includes('mac');
+    }
     private actions$ = inject(Actions);
     private dataService = inject(DataService);
     private dialog = inject(MatDialog);