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/components/note-editor/note-editor-full-page.tsx

@@ -25,14 +25,12 @@ import { useAiConsent } from '@/components/legal/ai-consent-provider'
 import { useState } from 'react'
 import { WikilinksBacklinksPanel } from '@/components/wikilinks-backlinks-panel'
 import { MemoryEchoSection } from '@/components/memory-echo-section'
-import { useRouter } from 'next/navigation'
 
 interface NoteEditorFullPageProps {
   onClose: () => void
 }
 
 export function NoteEditorFullPage({ onClose }: NoteEditorFullPageProps) {
-  const router = useRouter()
   const { t, language } = useLanguage()
   const { requestAiConsent } = useAiConsent()
   const dateLocale = language === 'fr' ? fr : enUS
@@ -66,10 +64,9 @@ export function NoteEditorFullPage({ onClose }: NoteEditorFullPageProps) {
   return (
     <>
       {/* ── outer container ── */}
-      <div className="h-screen flex items-stretch overflow-hidden transition-all duration-500">
-
+      <div className="flex flex-1 min-h-0 h-full w-full items-stretch overflow-hidden">
         {/* ── main scrollable column ── */}
-        <div className="flex-1 flex flex-col overflow-y-auto bg-white dark:bg-background">
+        <div className="flex-1 flex flex-col overflow-y-auto bg-white dark:bg-background min-w-0">
 
           {/* TOOLBAR */}
           <NoteEditorToolbar mode="fullPage" onClose={onClose} onToggleAttachments={() => setUploadTrigger(v => v + 1)} attachmentsCount={attachmentsCount} />