Add a version explainer page

[ObjectIsAdvantag]

Create a page such as:
/docs/about/versioning/

Possible title:
Understanding {mcpdesc} Versions

It would distinguish:

• Version What it represents Example
• Website release Version of the mcpdesc.org website and published content 0.9.0
• Specification version Version of the MCP Description format 0.7.0
• Tool version Release of an editor, validator, mock, or CLI Tool-specific
• Server version Version declared by an MCP server inside its description For example, 1.2.0
• MCP protocol version Protocol revision negotiated by MCP clients and servers Date-based protocol version

Why:

• The web site footer presents a version: 0.9.0 which could be confusing to the reader
• This is especially useful because an MCP Description example already contains another version under info.version, representing the described MCP server rather than the format itself.
• The Format page currently shows both mcpdesc: "0.7.0" and info.version: 1.0.0, so readers are already dealing with multiple independent version dimensions.

Approach:
in the site footer, use the terminology Web site release v0.9.0 (and link to the /docs/about/versioning/ page)