docs(mcp): fix granular policy lifecycle examples

[shiju-nv]

Summary

This PR makes the granular MCP policy examples usable by a conforming client. Each copied example permits the client initialize request and initialized notification before its existing tool allow and deny rules, while explaining that discovery is optional when the client already knows the tool names.

Related Issue

#2065

Changes

• Documentation change: Describe the required sequence as client initialize, successful server response, client notifications/initialized, then tool operations advertised by a server that negotiated the tools capability. Explain that the server response needs no client-to-server allow rule and that tools/list is optional when the client already knows the tool names.

Testing

• mise run pre-commit passes
• Unit tests added/updated
• E2E tests added/updated (if applicable)

Checklist

• Follows Conventional Commits
• Commits are signed off (DCO)
• Architecture docs updated (if applicable)