Bricks Builder MCP v1.5.7

v1.5.7 — Agent Skills system: 8 on-demand best-practice guides for AI agents

Adds two new MCP tools and 8 skill markdown files covering accessibility,
SEO/HTML, CSS best practices, performance, Bricks elements, dynamic data,
typography, and layout patterns. Skills are token-efficient: only a lightweight
index (~150 tokens) is included in bricks_get_session_context; full content
is loaded on demand via bricks_get_skill(slug) only when relevant to the task.

Closes #10

Co-Authored-By: Claude Sonnet 4.6 noreply@anthropic.com