Using ARG query to support Sql resource read operations

[ArthurMa1978]

What does this PR do?

This PR addresses part of the issue tracked in #756 by updating the SQL tool to eliminate its dependency on Azure.ResourceManager.Sql.
As a result, it reduces the AzureMCP agent size by approximately 6.41 MB.

GitHub issue number?

#756

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
  • Updated CHANGELOG.md for product changes (features, bug fixes, UI/UX, updated dependencies)
  • Spelling check passes: .\eng\common\spelling\Invoke-Cspell.ps1
• For MCP tool changes:
  • Updated README.md documentation
  • Updated command list in /docs/azmcp-commands.md
  • Updated test prompts in /e2eTests/e2eTestPrompts.md
  • For new or modified tool descriptions, ran the eng/tools/ToolDescriptionConfidenceScore tool and obtained a result >= 0.4
• 👉 For Community (non-Azure 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 azure - mcp to run Live Test Pipeline

[Copilot]

Pull Request Overview

This PR refactors the SQL tool to use Azure Resource Graph (ARG) queries instead of direct Azure Resource Manager (ARM) operations, eliminating the dependency on Azure.ResourceManager.Sql package and reducing the agent size by ~6.41 MB.

• Introduces BaseAzureResourceService for common Resource Graph query operations
• Replaces ARM-based SQL operations with Resource Graph queries
• Creates internal model classes to handle JSON deserialization from Resource Graph responses

Reviewed Changes

Copilot reviewed 21 out of 21 changed files in this pull request and generated 7 comments.

Show a summary per file

File	Description
core/src/AzureMcp.Core/Services/Azure/BaseAzureResourceService.cs	New base service class providing common Resource Graph query functionality
areas/sql/src/AzureMcp.Sql/Services/SqlService.cs	Refactored to use BaseAzureResourceService and Resource Graph queries
areas/sql/src/AzureMcp.Sql/Services/Models/*.cs	New internal model classes for deserializing SQL resource data from JSON
docs/new-command.md	Updated documentation explaining when to use Resource Graph vs direct ARM operations
areas/sql/tests/AzureMcp.Sql.LiveTests/SqlCommandTests.cs	Updated tests to use case-insensitive string comparisons

[jongio]

@copilot review this PR against checklist and guidance from new-command.md

[jongio]

Added consolidated review feedback referencing new-command.md checklist.

[Copilot]

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