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/feedback/Dialog.prompt.md

@@ -0,0 +1,17 @@
+Modal for propose-approve and destructive confirms; the title sits over a double stationery rule.
+
+```jsx
+<Dialog
+  open={open}
+  onClose={close}
+  title="Delete milestone"
+  footer={<>
+    <Button variant="ghost" onClick={close}>Keep it</Button>
+    <Button variant="danger" onClick={confirm}>Yes, delete</Button>
+  </>}
+>
+  This deletes the milestone and unhouses 12 issues. I'd like to hear you say yes.
+</Dialog>
+```
+
+Body copy may be Reginald's (serif if quoted). Escape and scrim-click close it.