Update README.md

[leestott]

Update intro with Mermaid and link to MCP protocol and specification change log

Describe the intention of the changes being proposed. What problem does it solve or functionality does it add?

Updating details and references

Does this introduce a breaking change?

When developers merge from main and run the server, azd up, or azd deploy, will this produce an error?
If you're not sure, try it out on an old environment.

[ ] Yes
[x] No

Does this require changes to learn.microsoft.com docs or modules?

which includes deployment, settings and usage instructions.

[ ] Yes
[x] No

Type of change

[ ] Bugfix
[ ] Feature
[ ] Code style update (formatting, local variables)
[ ] Refactoring (no functional changes, no api changes)
[x] Documentation content changes
[ ] Other... Please describe:

[Copilot]

Pull Request Overview

This PR enhances the MCP Core Concepts README by adding hyperlinks, a visual diagram, and a link to the latest protocol specification.

• Turned the introductory sentence into a linked reference to the Model Context Protocol GitHub organization
• Inserted a Mermaid flowchart illustrating the MCP client-server architecture
• Added a link to the 2025-06-18 protocol specification change log

Comments suppressed due to low confidence (3)

01-CoreConcepts/README.md:35

• [nitpick] The backslash in Local\Data Source A may be unintended and could confuse the diagram. Use Local Data Source A or a forward slash for clarity.

        S1 <--> D1[("Local\Data Source A")]

01-CoreConcepts/README.md:49

• [nitpick] For improved readability, consider adding a comma or semicolon after 'standard', e.g., 'evolving standard; you can see...'.

The MCP Protocol is an evolving standard you can see the latest updates to the [protocol specification](https://modelcontextprotocol.io/specification/2025-06-18/)

01-CoreConcepts/README.md:28

• [nitpick] The label has an unmatched parenthesis and 'VScode' is misspelled. Consider changing to something like Host['Host (with MCP, VS Code, IDEs, Tools)'].

        Host["Host with MCP VScode, IDEs, Tools)"]