refactor(git): migrate GetRepositoryTree to NewTool pattern

[SamMorrowDrums]

Summary

Convert GetRepositoryTree to use the NewTool pattern with ToolDependencies, removing the direct getClient parameter in favor of deps.GetClient.

Changes

• Converted GetRepositoryTree in git.go to use NewTool pattern
• Updated git_test.go to use new handler invocation pattern
• Updated tools.go to use direct function call instead of NewServerToolLegacy wrapper
• Removed duplicate test Test_RepositoriesGetRepositoryTree from repositories_test.go (canonical test is in git_test.go)

Stack

This PR is part of a stacked PR series to eliminate all NewServerToolLegacy usages:

• refactor: Separate ServerTool with HandlerFunc pattern and ToolDependencies #1589 - search.go ✅
• Migrate context_tools to new ServerTool pattern #1590 - context_tools.go ✅
• refactor(gists): migrate gists.go to NewTool pattern #1591 - gists.go ✅
• refactor(notifications): migrate notifications.go to NewTool pattern #1592 - notifications.go ✅
• Refactor repositories.go tools to use NewTool pattern with ToolDependencies #1593 - repositories.go ✅
• refactor(issues): migrate issues.go to NewTool pattern #1594 - issues.go ✅
• refactor(pullrequests): convert PR tools to NewTool pattern #1595 - pullrequests.go ✅
• Refactor actions.go to use NewTool pattern #1596 - actions.go ✅
• refactor(git): migrate GetRepositoryTree to NewTool pattern #1597 - git.go ← This PR

Testing

• All existing tests pass
• Linting passes

[Copilot]

Pull request overview

This PR refactors the GetRepositoryTree tool to use the NewTool pattern with ToolDependencies, eliminating another usage of the deprecated NewServerToolLegacy wrapper. This is part of a systematic refactoring across the codebase to standardize dependency injection for MCP tools.

Key changes:

• Converted GetRepositoryTree from returning separate tool and handler to returning toolsets.ServerTool
• Replaced direct getClient parameter with deps.GetClient for dependency injection
• Removed duplicate test from repositories_test.go (canonical test remains in git_test.go)

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated no comments.

File	Description
pkg/github/git.go	Refactored GetRepositoryTree to use NewTool pattern with ToolDependencies, replacing direct getClient parameter with deps.GetClient
pkg/github/git_test.go	Updated test to use new handler invocation pattern with ToolDependencies struct and toolDef.Handler(deps)
pkg/github/tools.go	Changed from NewServerToolLegacy wrapper to direct function call for GetRepositoryTree
pkg/github/repositories_test.go	Removed duplicate test Test_RepositoriesGetRepositoryTree (canonical version exists in git_test.go)