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/widgets/gps_compass.dart

@@ -50,7 +50,8 @@ class GpsCompass extends StatelessWidget {
     final theme = AppTheme.of(context);
 
     // No signal = subdued color, valid = foreground
-    final iconColour = _hasSignal ? theme.foreground : theme.highlight;
+    // Heading: foreground; acquiring: caution; no receiver at all: alarm.
+    final iconColour = _hasSignal ? theme.foreground : (_isAcquiring ? theme.caution : theme.alarm);
 
     // Convert to radians, 0 = no rotation when no signal
     final angle = _hasSignal ? (heading! * math.pi / 180.0) : 0.0;

lib/widgets/stat_box.dart

@@ -2,7 +2,7 @@
 // every readout is a box that takes its share of a row (`flex`) and sizes its type
 // from its own height, so a layout is a grid of boxes, and a value changing digits
 // never moves anything. Value in foreground with tabular figures, unit and label in
-// subdued; a warning turns the value to highlight.
+// subdued; a warning turns the value to alarm.
 //
 // Added for Yukart: [dim]. A missing or stale value is a normal state in a car
 // (app guideline 2), shown in subdued rather than hidden.
@@ -28,7 +28,7 @@ class StatBox extends StatelessWidget {
   final String label;
   final int flex;
 
-  /// If it returns true, the value shows in highlight.
+  /// If it returns true, the value shows in alarm.
   final bool Function()? isWarning;
 
   /// Missing or stale: the value shows in subdued.
@@ -41,7 +41,7 @@ class StatBox extends StatelessWidget {
     final valueColor = dim
         ? theme.subdued
         : warning
-        ? theme.highlight
+        ? theme.alarm
         : theme.foreground;
 
     return Expanded(
@@ -168,7 +168,7 @@ class StatBoxMain extends StatelessWidget {
                           color: dim
                               ? theme.subdued
                               : warning
-                              ? theme.highlight
+                              ? theme.alarm
                               : theme.foreground,
                           height: 1,
                         ),

lib/widgets/telltale.dart

@@ -7,7 +7,7 @@ import '../reading.dart';
 import '../theme/palette.dart';
 
 /// An on/off lamp in the boxed pattern: the label is the lamp. Lit in foreground
-/// (highlight when [warn]), dark in subdued; missing shows as a dash.
+/// (alarm when [warn]), dark in subdued; missing shows as a dash.
 class Telltale extends StatelessWidget {
   const Telltale({
     super.key,
@@ -32,7 +32,7 @@ class Telltale extends StatelessWidget {
     final missing = reading.value == null;
     final lit = reading.on && !reading.dim;
     final color = lit
-        ? (warn ? p.highlight : p.foreground)
+        ? (warn ? p.alarm : p.foreground)
         : p.subdued.withValues(alpha: missing ? 0.35 : 0.6);
     return Expanded(
       flex: flex,