Fix misplaced Unified MCP specs breaking lint

[Copilot]

The failing lint job was caused by a misplaced top-level RSpec.describe block in spec/bundleup/mcp_spec.rb, which triggered RSpec/MultipleDescribes. The same spec move also left spec/bundleup/unify/mcp_spec.rb asserting the old tools / tool API instead of the current list_tools / call_tool interface.

• Spec layout

  • Remove the stray BundleUp::Unify::MCP example group from spec/bundleup/mcp_spec.rb
  • Keep provider MCP coverage scoped to the provider MCP spec file only

• Unified MCP coverage

  • Update spec/bundleup/unify/mcp_spec.rb to match the current public API:
    • tools → list_tools
    • tool → call_tool
  • Preserve the existing handshake/session reuse assertions in the correct spec file

• Net effect

  • Restores one top-level example group per spec file
  • Aligns Unified MCP tests with the implementation without changing production code

describe '#list_tools' do
  it 'lists tools against the Unified server' do
    expect(unified.list_tools).to eq([tool])
  end
end

describe '#call_tool' do
  it 'requires a tool name' do
    expect { unified.call_tool('') }.to raise_error(ArgumentError, /Tool name is required/)
  end
end