Add word and character count feature that displays after timer completes

[kastrah]

This PR adds a word and character count feature that displays after timer completion.

Features:

• Shows word count and character count in the bottom toolbar
• Only appears after the timer session ends
• Automatically hides when starting a new timer session
• Maintains the app's minimalist design with subtle gray text

This enhancement helps users track their writing productivity without distracting them during the actual writing process.

[kastrah]

0415.mp4

how it works