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/tiptap-unique-id-extension.ts

@@ -1,8 +1,25 @@
 import { Extension } from '@tiptap/core'
 import { Plugin, PluginKey } from '@tiptap/pm/state'
+import type { Transaction } from '@tiptap/pm/state'
+import type { Node as PMNode } from '@tiptap/pm/model'
 
 const BLOCK_TYPES = ['paragraph', 'heading', 'blockquote', 'bulletList', 'orderedList', 'taskList', 'codeBlock']
 
+function assignMissingBlockIds(tr: Transaction, doc: PMNode) {
+  let modified = false
+  doc.descendants((node, pos) => {
+    if (!BLOCK_TYPES.includes(node.type.name)) return
+    if (node.attrs['data-id']) return
+
+    tr.setNodeMarkup(pos, undefined, {
+      ...node.attrs,
+      'data-id': generateBlockId(),
+    })
+    modified = true
+  })
+  return modified
+}
+
 function generateBlockId(): string {
   if (typeof crypto !== 'undefined' && typeof crypto.randomUUID === 'function') {
     return crypto.randomUUID()
@@ -17,6 +34,18 @@ function generateBlockId(): string {
 export const UniqueIdExtension = Extension.create({
   name: 'uniqueId',
 
+  onCreate({ editor }) {
+    const assign = () => {
+      if (editor.isDestroyed) return
+      const { tr, doc } = editor.state
+      if (assignMissingBlockIds(tr, doc)) {
+        editor.view.dispatch(tr)
+      }
+    }
+    assign()
+    requestAnimationFrame(assign)
+  },
+
   addProseMirrorPlugins() {
     return [
       new Plugin({
@@ -26,20 +55,7 @@ export const UniqueIdExtension = Extension.create({
           if (!hasDocChanged) return null
 
           const { tr, doc } = newState
-          let modified = false
-
-          doc.descendants((node, pos) => {
-            if (!BLOCK_TYPES.includes(node.type.name)) return
-            if (node.attrs['data-id']) return
-
-            tr.setNodeMarkup(pos, undefined, {
-              ...node.attrs,
-              'data-id': generateBlockId(),
-            })
-            modified = true
-          })
-
-          return modified ? tr : null
+          return assignMissingBlockIds(tr, doc) ? tr : null
         },
       }),
     ]