Add toolsnaps for every tool

[williammartin]

Description

Some time ago I introduced the idea of toolsnaps to highlight unintended changes to our tool schemas. I also imagined that it might have the benefit of quickly validating conformance if/when the project swaps to the official Go supported SDK. This PR backfills the toolsnaps to all tools.

Here's a reminder of what the error messages look like:

ok      github.com/github/github-mcp-server/internal/toolsnaps  (cached)
--- FAIL: Test_GetIssue (0.00s)
    issues_test.go:25:
                Error Trace:    /Users/williammartin/workspace/github-mcp-server/pkg/github/issues_test.go:25
                Error:          Received unexpected error:
                                tool schema for get_issue has changed unexpectedly:
                                @ ["annotations","title"]
                                - "Get issue details"
                                + "Get isse details"

                                run with `UPDATE_TOOLSNAPS=true` if this is expected
                Test:           Test_GetIssue
FAIL

Future Thoughts

Like with the desire to produce README's automatically from tool schemas, it would be better if there were a single data structure representing our tools, and then we could iterate that rather than relying on remembering to add the toolsnap call in each test.

[Copilot]

Pull Request Overview

Backfill toolsnaps invocations into all GitHub tool tests and generate corresponding snapshot files to catch unintended schema changes.

• Insert require.NoError(t, toolsnaps.Test(...)) in every tool test.
• Add a snapshot file under pkg/github/__toolsnaps__/ for each tool.
• Update the toolsnaps library’s error message to include instructions for updating snapshots.

Reviewed Changes

Copilot reviewed 55 out of 55 changed files in this pull request and generated no comments.

File	Description
internal/toolsnaps/toolsnaps.go	Augment error message to suggest UPDATE_TOOLSNAPS=true.
pkg/github/*_test.go	Invoke toolsnaps.Test in each tool’s test.
pkg/github/toolsnaps/*.snap	New snapshot files for every tool schema.

Comments suppressed due to low confidence (2)

pkg/github/search_test.go:21

• The call to require.NoError is unqualified because the require package isn't imported. Add import "github.com/stretchr/testify/require" to avoid compile errors.

	require.NoError(t, toolsnaps.Test(tool.Name, tool))

pkg/github/pullrequests_test.go:932

• Variable tool is undefined in this scope (only handler was assigned). Capture the tool return value before using it, e.g. tool, handler := UpdatePullRequestBranch(...).

			require.NoError(t, toolsnaps.Test(tool.Name, tool))