Add Topics navigation page with educational workout content

[Copilot]

This PR adds a new "Topics" navigation page to the workout timer application, providing users with educational content about different workout types and fitness tips.

Changes Made

Navigation Enhancement

• Added "topics" to the MODES tuple, positioned between "custom" and "settings" for logical grouping
• Added topics icon to the navigation icons dictionary
• Navigation now includes: Tabata → Boxing → Custom → Topics → Settings

New TopicsForm Component

Created a comprehensive educational page (TopicsForm) that includes:

• Tabata Training: Information about high-intensity interval training, the 20/10 protocol, and its benefits
• Boxing Training: Details about traditional boxing rounds and cardiovascular benefits
• Custom Workouts: Guidance on creating personalized interval patterns
• General Tips: Essential fitness advice for safe and effective training

Application Integration

• Updated _show_mode() method to handle topics mode (similar to settings page behavior)
• Modified _update_totals() and _on_start() to treat topics as a non-timer page
• Timer controls are properly disabled when topics page is active
• Summary section is hidden since no workout phases need to be displayed

User Experience

The Topics page provides:

• Scrollable content area for easy reading
• Consistent styling with the rest of the application
• Educational value that complements the timer functionality
• Clean, readable typography and layout

Technical Details

• Follows existing code patterns and inheritance structure (BaseModeForm)
• Returns empty phases list from estimate_phases() method
• Maintains backward compatibility
• Includes comprehensive testing and documentation

This enhancement transforms the application from a simple timer into a more complete workout companion by providing users with valuable educational content about the training methods they're using.

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• esm.ubuntu.com
  • Triggering command: /usr/lib/apt/methods/https (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

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