A full-screen TUI CLI agent powered by local LLMs via Docker Model Runner

feat(services): add DMR client, model registry, and OpenSpec integration master

- Add Docker Model Runner HTTP client with streaming chat - Add model registry with next/prev/setById cycling - Add thinking parser for reasoning-capable models - Add context-aware prompt suggestions per workflow step - Add OpenSpec hook to detect change state from filesystem - Add OpenSpec sync to vault with Obsidian frontmatter