Include `ql-mcp-client` in root build script and refactor CI workflow

[data-douser]

Problem

The ql-mcp-client Go binary is not built by the root npm run build script, and its CI workflow (client-integration-tests.yml) does not match the naming/structure patterns used by the server (build-server.yml) and extension (build-and-test-extension.yml) workflows. The integration tests run without a prior build/unit-test gate, wasting CI time when compilation or unit tests fail.

Desired State

• Root npm run build includes make -C client build alongside server and extension builds
• Rename workflow to build-and-test-client.yml for consistency
• Add a fast build-and-test-client job (Go build + unit tests + lint, no CodeQL) that gates the heavier integration test job via needs:
• Simplify step naming to match other workflows