Loope TUI Slash Commands Implementation Plan

Add a / command palette to the home prompt. All in the tui feature; no new deps. Commit once at the end.

Spec: TUI Slash Commands Spec

Tasks

tui/config.rs: RunOptions (max_iters, implementer, reviewers, designer, include_design, verify_command, dry_run) with Default, summary() -> String, config(requirement) -> LoopConfig, and make_invoker().
tui/command.rs: Command enum; SPECS (name, args, help); parse(&str) -> Result<Command, String>; matches(prefix) -> Vec<&Spec>; unit tests.

App: add options: RunOptions, palette state (palette: Vec<usize>, palette_selected), and message: Option<String>.
App::command_mode() (input starts with /), refresh_palette(), palette_up/down, complete_palette() (Tab), run_command() (parse + apply + set message). Settings commands mutate options; /browse//quit//help act; /apply defers to the event loop (needs the runs dir) via an intent like submit.
Session::start takes &RunOptions; the home launch builds from options.

handle_key (Home): in command mode, ↑/↓ move the palette, Tab completes, Enter runs the command, Esc clears to requirement mode; otherwise unchanged.
/apply: apply the selected run's changed-files.txt into the cwd (shared helper), report the count in the status message.

view/home.rs: a status line (options summary) above the input; when in command mode, render the palette (matching commands + descriptions, selection highlighted) above the input; show the transient message (red on error) in the footer.

Tests: command parsing/aliases/errors, palette filtering, each settings command mutating RunOptions, config() reflecting them, a render snapshot in command mode.
Docs: docs/guide/usage.md (a "Slash commands" subsection under Interactive TUI) and README. cargo clippy + tests green with and without --features tui. Commit.