feat: Allow Users to Configure Their Own Strava Athlete ID for Cloud Workout Sync

[SoNdA11]

Description

Currently, workout delivery through the cloud relies on manually configured Strava athlete IDs. To make the platform more flexible and scalable, users should be able to configure their own Strava Athlete ID directly within the application.

Proposed Solution

Add a settings page or configuration section where users can enter and manage their Strava Athlete ID. This ID would then be used by the cloud service when sending workouts to the user's Strava account.

Requirements

• Add a field for users to enter their Strava Athlete ID.
• Validate the input before saving.
• Store the ID securely in the user's profile/settings.
• Use the configured Athlete ID when processing cloud workout uploads or sync operations.
• Provide clear feedback if the ID is missing or invalid.

Benefits

• Eliminates the need for manual configuration by administrators.
• Allows multiple users to independently connect their own Strava accounts.
• Improves scalability and user autonomy.
• Simplifies the cloud workout delivery workflow.

Acceptance Criteria

• Users can save and update their Strava Athlete ID.
• The cloud workout sync process uses the user-configured ID.
• Invalid IDs are rejected with an appropriate error message.
• Existing functionality continues to work without regression.