Merge AppConfig key-value list and show into get

[alzimmermsft]

What does this PR do?

Merges the tools azmcp_appconfig_kv_list and azmcp_appconfig_kv_show into a single tool azmcp_appconfig_kv_get which can determine whether to list key-value settings based on where --key is used.

Adds two new parameters --key-filter and --label-filter to disambiguate functionality from --key and --label now that the same tool uses both sets of parameters. If both --key and --key-filter are passed to the tool it will fail validation, as this is ambiguous on which behavior should be used.

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
  • Updated servers/Azure.Mcp.Server/CHANGELOG.md and/or servers/Fabric.Mcp.Server/CHANGELOG.md for product changes (features, bug fixes, UI/UX, updated dependencies)
• 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
  • Updated command list in /docs/azmcp-commands.md and/or /docs/fabric-commands.md
  • 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

[Copilot]

Pull Request Overview

Consolidates the separate key-value list and show commands into a single unified get command for Azure App Configuration, adding filtering capabilities.

• Replaces KeyValueListCommand and KeyValueShowCommand with KeyValueGetCommand supporting both single retrieval and filtered listing.
• Introduces --key-filter and --label-filter options (but service implementation currently ignores them).
• Updates tests, documentation, serialization context, and changelog to reflect the merged command.

Reviewed Changes

Copilot reviewed 17 out of 17 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
KeyValueShowCommandTests.cs	Removed obsolete show command unit tests.
KeyValueListCommandTests.cs	Removed obsolete list command unit tests.
KeyValueGetCommandTests.cs	Added unit tests for new unified get command (missing some validation/filter coverage).
AppConfigCommandTests.cs	Updated live tests to use new get tool and array-based results.
IAppConfigService.cs	Merged list/show service methods into GetKeyValues; removed GetKeyValue.
AppConfigService.cs	Implemented merged GetKeyValues logic (currently ignores new filter parameters).
KeyValueShowOptions.cs	Removed obsolete options type.
KeyValueGetOptions.cs	Added unified options including new filter properties.
AppConfigOptionDefinitions.cs	Added key-filter/label-filter options; refactored option declarations.
KeyValueShowCommand.cs	Removed obsolete command.
KeyValueListCommand.cs	Removed obsolete command.
KeyValueGetCommand.cs	Added unified command with validation preventing ambiguous key + key-filter usage.
AppConfigJsonContext.cs	Updated JSON context to include new result type and remove old ones.
AppConfigSetup.cs	Registered new get command; removed list/show registrations.
CHANGELOG.md	Documented breaking change merging commands.
e2eTestPrompts.md	Updated prompts to reflect new get command and added filter scenarios.
azmcp-commands.md	Updated CLI usage examples for merged command and new filters.