Palette: seven roles (accent, good, caution added; highlight renamed alarm); no hard-coded colours left

background, foreground, subdued, accent (emphasis without danger), and the state
gradient good → caution → alarm; surface and onFill derived. smart-serow's
four-key themes still load (highlight = alarm; the new roles fall back).
Material's scheme follows: buttons in accent instead of the alarm colour.
Link state, mock banner, signal tiles, raw log, checklist button and marks,
camera page all take palette roles.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01DDwfd6Ki8UfG4hK6W5YpJz

lib/dash.dart

@@ -49,13 +49,13 @@ class DashPage extends StatelessWidget {
               children: [
                 if (b.mock)
                   Container(
-                    color: p.highlight,
+                    color: p.caution,
                     padding: const EdgeInsets.symmetric(vertical: 4),
                     child: Text(
                       'MOCK DATA — NOT FROM THE CAR',
                       textAlign: TextAlign.center,
                       style: TextStyle(
-                        color: p.background,
+                        color: p.onFill(p.caution),
                         fontWeight: FontWeight.w900,
                         letterSpacing: 2,
                       ),
@@ -186,8 +186,8 @@ class _DashBar extends StatelessWidget {
     final p = AppTheme.of(context);
     final (text, color) = switch (boundary.state) {
       LinkState.up => ('LINK', p.subdued),
-      LinkState.connecting => ('CONNECTING', p.highlight),
-      LinkState.down => ('NO LINK', p.highlight),
+      LinkState.connecting => ('CONNECTING', p.caution),
+      LinkState.down => ('NO LINK', p.alarm),
     };
     return SizedBox(
       height: 40,