Implement quick-add registry (task 21)

- Add url field to QuickAddAction; make action optional
- Add getQuickAdds() + SerializedQuickAddItem to registry so quick-add
  data can cross the server→client RSC boundary without serializing fns
- Update calendar/lists/notes manifests with navigation URLs
- QuickAddProvider wraps root layout: holds sheet/palette open state and
  global cmd/ctrl+k shortcut
- QuickAddSheet: bottom drawer on mobile, right-side popover on desktop,
  actions grouped by module
- CommandPalette: cmdk-powered modal with fuzzy filter and full keyboard
  nav (arrows + enter + esc)
- QuickAddFab: client button replacing the plain + stub in the dashboard
- Add .claude/** to ESLint ignores to prevent stale worktree artifacts
  from failing lint

All 4 E2E specs pass; typecheck, lint, and build clean.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/components/quick-add-provider.tsx

@@ -0,0 +1,57 @@
+"use client";
+
+import { createContext, useCallback, useContext, useEffect, useState } from "react";
+import type { SerializedQuickAddItem } from "@/modules/_core";
+
+type QuickAddState = {
+  sheetOpen: boolean;
+  paletteOpen: boolean;
+  openSheet: () => void;
+  closeSheet: () => void;
+  openPalette: () => void;
+  closePalette: () => void;
+  actions: SerializedQuickAddItem[];
+};
+
+const QuickAddContext = createContext<QuickAddState | null>(null);
+
+export function useQuickAdd() {
+  const ctx = useContext(QuickAddContext);
+  if (!ctx) throw new Error("useQuickAdd must be used inside QuickAddProvider");
+  return ctx;
+}
+
+export function QuickAddProvider({
+  children,
+  actions,
+}: {
+  children: React.ReactNode;
+  actions: SerializedQuickAddItem[];
+}) {
+  const [sheetOpen, setSheetOpen] = useState(false);
+  const [paletteOpen, setPaletteOpen] = useState(false);
+
+  const openSheet = useCallback(() => setSheetOpen(true), []);
+  const closeSheet = useCallback(() => setSheetOpen(false), []);
+  const openPalette = useCallback(() => setPaletteOpen(true), []);
+  const closePalette = useCallback(() => setPaletteOpen(false), []);
+
+  useEffect(() => {
+    function onKeyDown(e: KeyboardEvent) {
+      if ((e.metaKey || e.ctrlKey) && e.key === "k") {
+        e.preventDefault();
+        setPaletteOpen((prev) => !prev);
+      }
+    }
+    document.addEventListener("keydown", onKeyDown);
+    return () => document.removeEventListener("keydown", onKeyDown);
+  }, []);
+
+  return (
+    <QuickAddContext.Provider
+      value={{ sheetOpen, paletteOpen, openSheet, closeSheet, openPalette, closePalette, actions }}
+    >
+      {children}
+    </QuickAddContext.Provider>
+  );
+}