[codex] Add minimal Xcode Cloud MCP server

[backslash-f]

Summary

Add a first usable @thatfactory/xcode-cloud-mcp implementation as a minimal Node/TypeScript stdio MCP server for Xcode Cloud.

This PR intentionally keeps the feature set narrow:

• discover Xcode Cloud products and workflows
• list workflow build runs
• retrieve build issue counts
• retrieve and summarize text-like build logs
• retrieve test summaries and UI test artifact metadata

It also brings the repository to a publishable baseline with README setup docs for Claude and Codex, unit and smoke tests, and GitHub Actions for CI and nightly runs on the self-hosted macOS runner.

Why

The repository was effectively empty, so there was no installable MCP server yet.

This first cut establishes the minimal retrieval workflows needed for prompts like:

• retrieve logs of the latest failing build
• retrieve logs of build number X
• fetch test artifacts for the latest failing workflow run

while keeping the public surface small and simple enough to iterate on safely.

What changed

• added the Node/TypeScript package scaffold, build config, and npm metadata
• added App Store Connect authentication and HTTP client modules
• added MCP tools for discovery, build lookup, logs, issues, test summaries, and test artifacts
• added shared build locator validation with support for buildRunId, workflowId + buildNumber, and workflowId + buildSelector
• added log parsing helpers for plain text, gzip, and zip artifacts
• added unit tests and a stdio smoke test
• added CI and Nightly Tests GitHub workflows using [self-hosted, macOS]
• replaced the placeholder README with installation, configuration, badges, and usage docs

Validation

• npm test
• npm run build

Notes

• build lookup is workflow-scoped in this version
• binary artifacts remain metadata plus download URLs; this PR does not persist them locally
• deep .xcresult parsing is intentionally out of scope for v1