Add YAML tasks file support

[Doga0]

This PR adds YAML task file support while keeping the existing .txt behavior unchanged.

Since the repository only noted that YAML task files are not yet implemented, this PR proposes two minimal YAML shapes: a top-level list of prompt strings, and a tasks: list where each item can be either a string or an object with a prompt field.

Changes:

• Supports .yaml and .yml files in read_tasks_txt
• Keeps PyYAML optional via soft import
• Adds an optional yaml extra
• Updates CLI help and capture docs
• Adds tests for YAML task parsing and missing PyYAML behavior

[dacorvo]

@Doga0 thank you for your interest in the project, but we are not accepting external pull-requests until the code is more polished. We are in the middle of a migration to a full rust client from the python protoype application.

[Doga0]

@Doga0 thank you for your interest in the project, but we are not accepting external pull-requests until the code is more polished. We are in the middle of a migration to a full rust client from the python protoype application.

Hello, thanks for the clarification. This is my first attempt to contribute to an open-source project 😅I would be happy to contribute again once external contributions are welcome. Good luck with the migration