feat(app): Add enums, models, and schemas for Task and Task Groups

[Jarro01X]

Checklist

• [X] Read CONTRIBUTING.md.
• [X] PR title is short and non-generic (see previously merged PRs for examples).
• [X] PR only implements a single feature or fixes a single bug.
• [X] Tests passing (uv run pytest tests)?
• [X] Lint / pre-commits passing (pre-commit run --all-files)?

Description

This is a pull request to check for potential issues with the data models of task and task groups

Related Issues

No related issues

Screenshots / Recordings

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Steps to QA

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