Add workouts screen with filtering and sorting

[Copilot]

Adds a dedicated workouts list view to browse and manage all workouts with filter and sort capabilities.

Changes

New WorkoutsView

• Displays all workouts from WorkoutManager in scrollable list
• Filter by status: Scheduled, Completed, Skipped, In Progress
• Sort by date (ascending/descending) or title
• WorkoutCard component shows date, status badge, metrics (duration, power, intensity)
• Empty state handling with contextual messaging
• Navigates to existing WorkoutDetailView on tap

ViewModel

• WorkoutsViewModel manages state with @Published properties
• Computed filteredAndSortedWorkouts applies filter/sort logic reactively
• Enum-based SortOption for type safety

Integration

• Added to main menu in ContentView between "Training Plan" and "AI Workout Generator"
• Uses figure.indoor.cycle SF Symbol for consistency

Testing

• 8 unit tests: filter/sort logic, boundary conditions
• 5 UI tests: navigation, interaction, empty states

// Example usage in ContentView
NavigationLink(destination: WorkoutsView()) {
    Label("Workouts", systemImage: "figure.indoor.cycle")
}

All components follow existing accessibility patterns and design language (SF Symbols, 12pt rounded corners, status badge colors).

Original prompt

Add a new workouts screen

[Variant 3 of 3]

The user has attached the following files as relevant context:

• .github/instructions/run.instructions.md
• .github/copilot-instructions.md
• docs/memory.md

Created from VS Code via the GitHub Pull Request extension.

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