Adds an rmcp-based stdio MCP client in harness-mcp plus adapters exposing a configured server's tools as namespaced harness-tools, with an echo-server fixture and integration test, and wiring through harness-app.
Adds the jobs pane to the TUI with a new snapshot test, subtask drill-in navigation, and periodic reminders injected into the engine loop for long-running background jobs.
Adds a bundled models.dev snapshot plus harness-providers::modelsdev to resolve model metadata, and wires live cost display into the TUI's input bar and message state, updating the render snapshots accordingly.
Builds the ratatui TUI: EngineHandle bridging the async engine to the render loop, chat viewport rendering with a markdown renderer, input handling, a permission modal wired to the real oneshot ask path, and a session picker. Adds TestBackend snapshot tests covering empty session, tool cards (running/completed/error), permission modal, session picker, and message rendering.
Adds the harness-app composition root wiring config, providers, tools, and the engine loop together, plus the harness run -p "<prompt>" debug command in harness-tui::main for driving a one-shot prompt end-to-end from the CLI.
Sets up the Cargo workspace (harness-core, harness-tools, harness-providers, harness-mcp, harness-lsp, harness-app, harness-tui) and the ten architecture docs under docs/. harness-core gets its foundational types (session/message/part/model ids), an in-process event bus, a table-driven permission evaluate function, and a SQLite-backed storage actor with schema and roundtrip coverage. Every crate compiles empty and a bin stub prints its version.
darman