Scaffold CommiTea: yarn workspaces, Electron shell, core label schema, design system

- apps/desktop: electron-vite + React + Tailwind mapped onto design tokens
  (preflight off; tokens/base.css owns the reset); boots to a Reginald
  placeholder proving fonts/tokens/core wiring
- packages/core: pure TS; gitea label schema (est/*, p/*, deadline/hard)
  with pessimistic conflict resolution + 15 unit tests
- docs/design: full design handoff (tokens, 16 component contracts,
  interactive 14-screen prototype, Reginald voice rules)
- docs/PLAN.md: product plan (purity rule, pm-state repo, deterministic
  scheduler + Monte Carlo, directive log)
- Deliberate deviation from novelpad stack: no ElectricSQL/PGlite — local
  store is a rebuildable cache over gitea REST/webhooks (better-sqlite3
  in main process, arriving in P1)

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

docs/design/components/core/Tabs.js.txt

@@ -0,0 +1,54 @@
+import React from 'react';
+import { Icon } from './Icon';
+
+const CSS = `
+.ct-tabs {
+  display: flex; gap: 2px;
+  border-bottom: 1px solid var(--border-hairline);
+}
+.ct-tab {
+  display: inline-flex; align-items: center; gap: 7px;
+  font: 500 13.5px/1 var(--font-sans);
+  color: var(--ink-2);
+  background: none; border: none;
+  padding: 10px 12px;
+  margin-bottom: -1px;
+  border-bottom: 2px solid transparent;
+  cursor: pointer;
+  transition: color var(--duration-fast) var(--ease-out);
+}
+.ct-tab:hover { color: var(--ink-1); }
+.ct-tab--active {
+  color: var(--ink-1);
+  font-weight: 600;
+  border-bottom-color: var(--accent);
+}
+.ct-tab__count { font: 400 11.5px/1 var(--font-mono); color: var(--ink-3); }
+`;
+(function inject() {
+  if (typeof document !== 'undefined' && !document.getElementById('ct-tabs-css')) {
+    const s = document.createElement('style'); s.id = 'ct-tabs-css'; s.textContent = CSS;
+    document.head.appendChild(s);
+  }
+})();
+
+export function Tabs({ items, active, onChange, style, ...rest }) {
+  return (
+    <div className="ct-tabs" role="tablist" style={style} {...rest}>
+      {items.map((item) => (
+        <button
+          key={item.id}
+          type="button"
+          role="tab"
+          aria-selected={item.id === active}
+          className={`ct-tab${item.id === active ? ' ct-tab--active' : ''}`}
+          onClick={() => onChange && onChange(item.id)}
+        >
+          {item.icon ? <Icon name={item.icon} size={15} /> : null}
+          {item.label}
+          {item.count != null ? <span className="ct-tab__count">{item.count}</span> : null}
+        </button>
+      ))}
+    </div>
+  );
+}