Redesign Dashboard + add WorkoutSelectPage

Dashboard (cleaner):
- Week calendar at TOP
- Coach greeting (workout today or rest tips)
- If workout: gradient card with arrow → WorkoutPage
- If rest: tips + '+ Lägg till pass' → WorkoutSelectPage
- Quick stats at bottom

WorkoutSelectPage:
- Visual workout cards with icons and colors
- Preview of exercises
- Select + Start flow
- Fixed bottom action button

frontend/src/App.jsx

@@ -4,6 +4,7 @@ import Dashboard from './pages/Dashboard'
 import ProfilePage from './pages/ProfilePage'
 import ProgressPage from './pages/ProgressPage'
 import WorkoutPage from './pages/WorkoutPage'
+import WorkoutSelectPage from './pages/WorkoutSelectPage'
 import './App.css'
 
 const API_URL = '/api'
@@ -116,6 +117,16 @@ function App() {
     return <ProgressPage onBack={() => setView('dashboard')} />
   }
 
+  // Workout select page
+  if (view === 'select-workout') {
+    return (
+      <WorkoutSelectPage 
+        onBack={() => setView('dashboard')}
+        onSelectWorkout={startWorkout}
+      />
+    )
+  }
+
   // Workout view
   if (view === 'workout' && selectedDay) {
     return (