Add an AI provider to ClaudeBar as a JSON definition run by the one generic Provider and DataSource. Use this skill when: (1) Adding a new AI assistant provider (like Antigravity, Cursor, etc.) (2) A provider needs a setting, an added account, or an old saved key kept working (3) A provider's CLI, API or file format changed and its definition must follow (4) User asks "how do I add a new provider" or "create a provider for X"