docs: warn against concurrent Studio Pro and mxcli editing (#36)

Studio Pro maintains in-memory caches that cannot be updated externally.
Editing a project with mxcli while it is open in Studio Pro causes
version control sync errors.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: ako

README.md

@@ -1,6 +1,8 @@
 # mxcli - Mendix CLI for AI-Assisted Development
 
 > **WARNING: Alpha-quality software.** This project is in early stages and has been largely vibe-engineered with AI coding assistants. Expect bugs, missing features, and rough edges. **mxcli can corrupt your Mendix project files** — always work on a copy or use version control. Use at your own risk. This has been developed and tested against Mendix 11.6, other versions are currently not validated.
+>
+> **Do not edit a project with mxcli while it is open in Studio Pro.** Studio Pro maintains in-memory caches that cannot be updated externally. Close the project in Studio Pro first, run mxcli, then re-open the project.
 
 A command-line tool that enables AI coding assistants ([Claude Code](https://claude.ai/claude-code), Cursor, Continue.dev, Windsurf, Aider, and others) to read, understand, and modify Mendix application projects.
 

docs-site/src/preface/what-is-mxcli.md

@@ -18,6 +18,8 @@
 
 A developer or AI agent writes MDL statements. mxcli parses and validates them, then applies the changes directly to the `.mpr` project file. The modified project can then be opened in Mendix Studio Pro as usual.
 
+> **Important:** Do not edit a project with mxcli while it is open in Studio Pro. Studio Pro maintains in-memory caches that cannot be updated externally, and concurrent edits will cause errors. Close the project in Studio Pro first, run mxcli, then re-open the project.
+
 ## Key Capabilities
 
 - **Project exploration** -- list modules, entities, microflows, pages; describe any element in MDL; full-text search across all strings and source definitions.