feat: editor improvements and architectural grid prototype

Multiple feature additions and improvements across the application:

- NextGen Editor: drag handles, smart paste, block actions
- Structured views: Kanban and table layouts for notes
- Architectural Grid: new brainstorming/agent interface prototype
- Flashcards: SM-2 revision algorithm with AI generation
- MCP server: robustness improvements
- Graph/PDF chat: fix click propagation and copy behavior
- Various UI/UX enhancements and bug fixes

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

memento-note/app/(main)/home/page.tsx

@@ -2,12 +2,7 @@ import { cookies } from 'next/headers'
 import { getAllNotes } from '@/app/actions/notes'
 import { getAISettings } from '@/app/actions/ai-settings'
 import { HomeClient } from '@/components/home-client'
-import {
-  NOTES_LAYOUT_COOKIE,
-  NOTES_VIEW_TYPE_COOKIE,
-  parseNotesLayoutMode,
-  parseNotesViewType,
-} from '@/lib/notes-view-preference'
+import { NOTES_LAYOUT_COOKIE, parseNotesLayoutMode } from '@/lib/notes-view-preference'
 
 export default async function HomePage() {
   const [allNotes, settings, cookieStore] = await Promise.all([
@@ -17,13 +12,11 @@ export default async function HomePage() {
   ])
 
   const initialLayoutMode = parseNotesLayoutMode(cookieStore.get(NOTES_LAYOUT_COOKIE)?.value)
-  const initialViewType = parseNotesViewType(cookieStore.get(NOTES_VIEW_TYPE_COOKIE)?.value)
 
   return (
     <HomeClient
       initialNotes={allNotes}
       initialLayoutMode={initialLayoutMode}
-      initialViewType={initialViewType}
       initialSettings={{
         showRecentNotes: settings?.showRecentNotes !== false,
         noteHistory: settings?.noteHistory === true,