Enforce code styles in build

[Alan Zimmer (alzimmermsft)]

What does this PR do?

Makes some changes to the build to enforce code style rules while building the project and enabling more diagnostics to be raised.

• Standardized verbiage for CancellationToken parameters.
• Require all CSharp files to have header Copyright (c) Microsoft Corporation.\nLicensed under the MIT License..
• Made incorrect CSharp modifier order an error instead of a suggestion.
• Require using directives to be outside of namespace scope.
• Require namespace to be defined using file scoping instead of block scoping.
• Require namespace to match folder structure.
• Raise an error on any unused parameters, including public APIs as we ship as a compiled binary and not an SDK.
• Raise an error on unused using directives.
• Raise an error on invalid string formatting.
• Raise an error on unused and unread private members.
• Raise an error when a synchronous method is declared asynchronous.
• Validate doc string formatting (missing closing tags, unescaped special character) and require cref types to be declared in using directives correctly.

And fixed / suppressed (when valid to do so) all found issues due to the enforcement of the above.

GitHub issue number?

[Link to the GitHub issue this PR addresses]

Pre-merge Checklist

• Required for All PRs
  • Read contribution guidelines
  • PR title clearly describes the change
  • Commit history is clean with descriptive messages (cleanup guide)
  • Added comprehensive tests for new/modified functionality
  • Created a changelog entry if the change falls among the following: new feature, bug fix, UI/UX update, breaking change, or updated dependencies. Follow the changelog entry guide
• For MCP tool changes:
  • One tool per PR: This PR adds or modifies only one MCP tool for faster review cycles
  • Updated servers/Azure.Mcp.Server/README.md and/or servers/Fabric.Mcp.Server/README.md documentation
  • Validate README.md changes running the script ./eng/scripts/Process-PackageReadMe.ps1. See Package README
  • For new or modified tool descriptions, ran ToolDescriptionEvaluator and obtained a score of 0.4 or more and a top 3 ranking for all related test prompts
  • For tools with new names, including new tools or renamed tools, update consolidated-tools.json
  • For renamed tools, follow the Tool Rename Checklist and tag the PR with the breaking-change label
  • For new tools associated with Azure services or publicly available tools/APIs/products, add URL to documentation in the PR description
• Extra steps for Azure MCP Server tool changes:
  • Updated command list in servers/Azure.Mcp.Server/docs/azmcp-commands.md
  • Ran ./eng/scripts/Update-AzCommandsMetadata.ps1 to update tool metadata in azmcp-commands.md (required for CI)
  • Updated test prompts in servers/Azure.Mcp.Server/docs/e2eTestPrompts.md
  • 👉 For Community (non-Microsoft team member) PRs:
    • Security review: Reviewed code for security vulnerabilities, malicious code, or suspicious activities before running tests (crypto mining, spam, data exfiltration, etc.)
    • Manual tests run: added comment /azp run mcp - pullrequest - live to run Live Test Pipeline

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