fix: tmpo pause and tmpo resume now correctly accounts for project context switching

[DylanDevelops]

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 the logic for resuming time tracking sessions to ensure that the resumed session is always associated with the current project. The resume command now looks up the last stopped entry for the detected project, rather than globally, and provides more accurate error messages. The database logic and tests have also been updated to support this change.

Resume command improvements:

• The resume command now resumes the last stopped session specifically for the currently configured project, rather than any project. This ensures users only resume sessions relevant to their current context. [1] [2]
• Error messages when no previous session is found are now project-specific, making it clearer to the user why resuming failed.

Database layer changes:

• Added a new method GetLastStoppedEntryByProject to the Database class in internal/storage/db.go, which retrieves the last stopped entry for a given project.
• Updated imports in cmd/tracking/resume.go to include the project package, used for detecting the current project.

Testing improvements:

• Added comprehensive tests for GetLastStoppedEntryByProject in internal/storage/db_test.go, covering multiple scenarios and edge cases.