Fix dismiss_notification rejecting valid HTTP 204 response

[Copilot]

Summary

The dismiss_notification tool incorrectly rejected HTTP 204 (No Content) responses from the GitHub API as failures, despite 204 being the documented success status for marking notifications as done.

Why

When users marked notifications as done, the operation succeeded but reported: failed to mark notification as done: unexpected status 204:

What changed

• Added http.StatusNoContent (204) to accepted success status codes in DismissNotification handler
• Added test coverage for 204 response on "mark as done" operation

MCP impact

• No tool or API changes — Internal bug fix only; tool behavior now matches GitHub API contract.

Prompts tested (tool changes only)

N/A — No user-facing tool changes

Security / limits

• No security or limits impact

Tool renaming

• I am not renaming tools as part of this PR

Lint & tests

• Linted locally with ./script/lint
• Tested locally with ./script/test

Docs

• Not needed

Original prompt

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This section details on the original issue you should resolve

<issue_title>dismiss_notification reports failure on successful 204 response</issue_title>
<issue_description>When using the dismiss_notification tool to mark notifications as done, the operation succeeds (HTTP 204 No Content) but the tool reports it as a failure:

failed to mark notification as done: unexpected status 204:

HTTP 204 is the expected success response for this endpoint per the GitHub API documentation.

Expected behavior: The tool should return success when receiving a 204 response.

Actual behavior: The tool returns an error message indicating failure despite the operation completing successfully.</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes dismiss_notification reports failure on successful 204 response #1817

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[Copilot]

Pull request overview

This PR fixes a bug in the dismiss_notification tool where HTTP 204 (No Content) responses from GitHub's API were incorrectly treated as failures. The GitHub API returns 204 as the documented success status when marking notifications as done, so this change aligns the code with the actual API contract.

Changes:

• Added http.StatusNoContent (204) to the accepted success status codes in the DismissNotification handler
• Added test case for 204 response when marking notifications as done
• Renamed existing test case to clarify it tests 200 response scenario

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
pkg/github/notifications.go	Added HTTP 204 status code to success condition check for dismiss notification operation
pkg/github/notifications_test.go	Added test case for 204 response and clarified existing test naming to distinguish 200 vs 204 scenarios