style: minimalist Material icon buttons (download, upload, delete)

- DashcamScreen: Download + Delete as IconButton with Icons.Filled
- DownloadsScreen: CloudUpload + Delete as IconButton
- No text labels, just clean Material icons

templates/base.html

@@ -19,7 +19,7 @@
     {# ── Desktop sidebar ─────────────────────────────────────────────────── #}
     <nav id="app-sidebar" class="app-sidebar d-none d-md-flex flex-column">
         <a class="sidebar-brand" href="{{ url_for('index') }}" aria-label="Home">
-            <span class="sidebar-brand-logo">yaris-obd</span>
+            <span class="sidebar-brand-logo">YARIS-OBD</span>
         </a>
         <hr class="sidebar-divider">
         <ul class="nav flex-column flex-grow-1">
@@ -67,7 +67,7 @@
             <div class="container-fluid px-3 gap-2">
                 {# Mobile: logo on left #}
                 <a class="navbar-brand d-flex d-md-none align-items-center gap-2 text-decoration-none" href="{{ url_for('index') }}">
-                    <span style="font-family:'Racing Sans One','Arial Black',sans-serif;font-size:1.3rem;font-style:italic;color:#1c1c1e;">yaris-obd</span>
+                    <span style="font-family:'Racing Sans One','Arial Black',sans-serif;font-size:1.3rem;font-style:italic;color:#1c1c1e;">YARIS-OBD</span>
                 </a>
                 <div class="ms-auto d-flex align-items-center gap-2">
                     <div class="dropdown">