Added documentation for internal/currency, internal/update, and internal/ui modules. Updated CONTRIBUTING.md and CLAUDE.md to reflect new directory structure and responsibilities. Revised export CSV and JSON examples in usage docs to match new field order and naming. Clarified project initialization steps in usage documentation.

Pull Request Checklist

• I have read and followed the contribution guidelines.
• My pull request targets the main branch of tmpo.
• I have tested these changes locally on my machine.

Description

This pull request updates documentation to reflect recent structural and feature changes to the project. It adds descriptions for new internal packages, updates export format examples, and clarifies configuration and initialization workflows.

Documentation of new internal packages and features:

• Added descriptions for new internal packages: currency (for currency formatting and symbol handling), update (for update checking from GitHub releases), and expanded ui (for formatting, colors, and terminal output) in both CONTRIBUTING.md and CLAUDE.md. [1] [2] [3]
• Updated the CLI structure documentation to include the new config/ subdirectory under cmd/.

Export format and usage documentation updates:

• Updated CSV and JSON export examples in docs/usage.md to match the new field order and naming conventions, including explicit start_time, end_time, and duration_hours fields. [1] [2]
• Clarified the interactive prompts for project initialization in usage examples, showing step-by-step prompts for setting project name, hourly rate, and description.

Formatting and clarity improvements:

• Specified code block language as text for configuration directory structure in docs/configuration.md for improved readability.