feat(ai-commit): refactor context configuration and remove hardcoded provider settings to enable dynamic module-controlled options. Implement conditional logic in `generator.lua` for recent commits, OpenCode data, and staged changes based on configurable flags via `context.values`. Delete legacy `preferences.lua` file with direct model selection code; move all provider/model configuration to centralized AI Provider service which now handles runtime caching and consumer picker integration without waiting for plugin load. master