chore: remove dead code — 8 components, 5 libs, 4 API routes, 4 npm packages, 30+ scripts, dead CSS, dead exports

Removed unused components:
- brainstorm-canvas, brainstorm-create-dialog, invite-dialog, manual-idea-dialog
- note-inline-editor, profile-page-header, quota-paywall, label-management-dialog

Removed dead lib files:
- api-auth.ts, color-harmony-recommendation.ts, label-storage.ts, modern-color-options.ts
- hooks/use-card-size-mode.ts

Removed dead API routes:
- ai/test-chat, ai/test-embeddings, ai/test-tags, admin/randomize-labels

Removed unused npm packages:
- cmdk, novel, tippy.js, react-force-graph-2d

Cleaned dead CSS from globals.css:
- acrylic-*, win11-shadow-*, muuri-grid/item, ai-glass, ai-tab-indicator, ai-send-btn, sidebar-view-toggle, memento-sidebar-depth

Removed 29 orphan scripts and 3 root orphan files

Cleaned dead exports from 8 lib files:
- NOTE_TYPE_CONFIG, getPublishableKey, PROVIDER_DEFAULTS, useNotes/useNote/invalidateNote, etc.

memento-note/lib/stripe.ts

@@ -11,8 +11,4 @@ export const stripe = new Stripe(process.env.STRIPE_SECRET_KEY ?? 'sk_test_place
   typescript: true,
 });
 
-export function getPublishableKey(): string {
-  const key = process.env.NEXT_PUBLIC_STRIPE_PUBLISHABLE_KEY;
-  if (!key) throw new Error('NEXT_PUBLIC_STRIPE_PUBLISHABLE_KEY is not set');
-  return key;
-}
+