Skills and model picker fixes

This release introduces Skills: local markdown workflows that help SupaPM follow your preferred ways of working.

Skills are stored locally and included in AI context as metadata. When the assistant decides a skill is relevant, it can load the full instructions and apply them to the task.

What's new

• Skills: Create local markdown workflows for repeatable product-management tasks.
• Better AI model picker: The model picker now more accurately reflects what each provider exposes and supports.

This is the first step toward making SupaPM feel less like a generic chat assistant and more like a teammate that knows your operating style.