improved pattern/allowed in slot docs

[kamsar]

This pull request updates the documentation in rules/uniform.mdc to clarify concepts related to Uniform Components, Slots, Patterns, and their attributes. The changes aim to improve the understanding of configuration options and content reuse within Uniform.

⚠️ do not land this PR until mcp-next is deployed to the platform or else the instructions will contain inaccurate information.

Enhancements to Uniform Slot Definitions:

• Expanded explanation of how slot definitions control which components or patterns are allowed, including properties like allowAllComponents, allowedComponents, and patternsInAllowedComponents. Added examples for clarity.

Improvements to Uniform Patterns:

• Detailed the types of Uniform Patterns—Component Patterns, Composition Patterns, and Entry Patterns—and their use cases for content reuse and template-based creation.

Clarifications to Uniform Component Slots:

• Updated the description of slots to include the possibility of inserting component patterns, not just individual components.

MCP/AI Limitations:

• Added a note specifying that MCP/AI cannot access published content and can only work with drafts, along with instructions for requesting publication.