feat(watch): clôture lot #91 - fréquence cardiaque live, notifications de séance et finitions montre

Consolide le lot applicatif watch companion validé :
- télémétrie fréquence cardiaque live remontée montre -> téléphone
  (collecteur watch, adapter Wear Data Layer, persistance Drift,
  propagation aux écrans historique/programme/profil/exécution)
- notifications de séance en arrière-plan côté téléphone (service
  foreground de statut + passerelle applicative)
- finitions montre : chrono d'étape, score d'étape, retrait du bouton
  "lancer une séance", thème, icônes et polices watch_app

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

watch_app/lib/presentation/watch_theme.dart

@@ -9,23 +9,41 @@ ThemeData watchTheme() {
 
   final textTheme = Typography.whiteMountainView.copyWith(
     labelSmall: const TextStyle(
+      fontFamily: 'Archivo',
       fontSize: 10,
       fontWeight: FontWeight.w800,
       color: muted,
+      letterSpacing: 0,
+    ),
+    bodySmall: const TextStyle(
+      fontFamily: 'Archivo',
+      fontSize: 11,
+      color: muted,
+      height: 1.15,
+      letterSpacing: 0,
+    ),
+    bodyMedium: const TextStyle(
+      fontFamily: 'Archivo',
+      fontSize: 13,
+      color: text,
+      height: 1.15,
+      letterSpacing: 0,
     ),
-    bodySmall: const TextStyle(fontSize: 11, color: muted, height: 1.15),
-    bodyMedium: const TextStyle(fontSize: 13, color: text, height: 1.15),
     titleSmall: const TextStyle(
+      fontFamily: 'Archivo',
       fontSize: 16,
       fontWeight: FontWeight.w800,
       color: text,
       height: 1.05,
+      letterSpacing: 0,
     ),
     displayLarge: const TextStyle(
-      fontSize: 44,
-      fontWeight: FontWeight.w900,
-      color: text,
+      fontFamily: 'Anton',
+      fontSize: 42,
+      fontWeight: FontWeight.w400,
+      color: Color(0xFFC9A24A),
       height: 0.95,
+      letterSpacing: 0,
       fontFeatures: [FontFeature.tabularFigures()],
     ),
   );
@@ -50,8 +68,10 @@ ThemeData watchTheme() {
         padding: const EdgeInsets.symmetric(horizontal: 14, vertical: 10),
         shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(8)),
         textStyle: textTheme.labelLarge?.copyWith(
+          fontFamily: 'Archivo',
           fontSize: 13,
           fontWeight: FontWeight.w800,
+          letterSpacing: 0,
         ),
       ),
     ),
@@ -62,8 +82,10 @@ ThemeData watchTheme() {
         side: const BorderSide(color: Color(0xFF303748)),
         shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(8)),
         textStyle: textTheme.labelLarge?.copyWith(
+          fontFamily: 'Archivo',
           fontSize: 13,
           fontWeight: FontWeight.w800,
+          letterSpacing: 0,
         ),
       ),
     ),