Add PWA service worker (via vite plugin), use dynamic viewport units for interface size (improves mobile experience), replace default vue homepage with basic info

frontend/src/components/TitleBar.vue

@@ -7,7 +7,7 @@
 </script>
 
 <template>
-  <header>
+  <header class="main-header">
     <button class="when-sidebar-collapsed" @click="sidebarExpand()">
       >>
     </button>
@@ -20,14 +20,6 @@
 </template>
 
 <style scoped>
-  header {
-    height: 3em;
-    border-bottom: 1px solid var(--color-border);
-    display: flex;
-    flex-direction: row;
-    align-items: center;
-  }
-
   :slotted(h1) {
     font-size: 160%;
     font-weight: bold;

frontend/src/components/main/Sidebar.vue

@@ -80,7 +80,7 @@
 </script>
 
 <template>
-  <aside class="sidebar" :style="sidebarStyle()" v-if="sidebarExpanded">
+  <aside class="main-sidebar" :style="sidebarStyle()" v-if="sidebarExpanded">
     <div class="drag-bar" @mousedown="dragBarMouseDown($event)"></div>
     <div class="tab-bar">
       <div class="tab-group">
@@ -109,14 +109,6 @@
 </template>
 
 <style scoped>
-  .sidebar {
-    display: flex;
-    flex-direction: column;
-    position: relative;
-    z-index: var(--z-index-sidebar);
-    background-color: var(--color-background);
-  }
-
   .tab-bar, .tab-group {
     display: flex;
     flex-direction: row;