feat: ⌘K command palette (fuzzy search, grouped, keyboard-first)

[hellno]

⌘K Command palette

A Superhuman/Linear-style command palette, built on gpui-component's List + ListDelegate
(the same searchable-list primitive Zed's own palette uses — so search, keyboard nav, scrolling
and selection come for free).

What you get

• Floating, top-anchored panel over a soft dark scrim (correct in light and dark).
• Fuzzy search with the matched characters highlighted in the accent color.
• Commands grouped by category (Recent → Navigation → Create → Appearance → App), with a
  Recent group that floats recently-run commands out of their category (Raycast/Spotlight style).
• Live shortcut chips derived from the keymap — change a KeyBinding and the chip follows.
• First row pre-selected; click or ↵ to run, esc/backdrop to close; footer hint bar; subtle fade-in.

The "shadcn" promise — adding a command is one line

It dispatches the same gpui action as the hotkey and the menu, so the three can never drift:

Command { id: "home", title: "Go Home", icon: IconName::ArrowLeft,
          category: Category::Navigation, keywords: &["back", "welcome"],
          run: Run::Action(|| Box::new(GoBack)) }

A small Run enum (Action | Accent) keeps the registry a clean literal; an ## Extending doc
block covers new Run variants, categories, and persistent recents.

How it's wired

• TogglePalette action + secondary-k keybinding + a View-menu item (main.rs).
• Shell owns the open/closed state, rebuilds a fresh ListState each open (query always starts
  empty), and renders the overlay as its last child (shell.rs).
• The delegate can't reach Shell, so running a command is bridged through ListEvent: the
  delegate stashes the chosen command, Shell::on_palette_event drains it, closes the palette,
  then dispatches (so the action lands on Shell's focus tree).
• Compact, dependency-free fuzzy matcher (prefix / word-boundary / consecutive bonuses; returns
  match ranges for highlighting) with 6 unit tests.

Files

• New: src/command_palette.rs (registry, matcher, delegate, overlay, tests)
• Wiring: src/main.rs, src/shell.rs
• Docs: README.md (Command palette section), docs/LEARNINGS.md §16 (load-bearing details + gotchas)

Quality

cargo check + clippy clean (0 warnings) · fmt applied · 6 matcher tests pass · verified
running in light and dark. Reviewed by a multi-agent pass (correctness / DX / design) with each
finding verified against source; the confirmed polish items (light-mode scrim, selected-row icon,
long-title truncation, extension docs) are included.

🤖 Generated with Claude Code