refactor: switch mindmap layout from d3-hierarchy to dagre with word wrapping

package.json

@@ -43,8 +43,7 @@
     "@testing-library/react": "^16.3.2",
     "@testing-library/user-event": "^14.6.1",
     "@types/chokidar": "^1.7.5",
-    "@types/d3-hierarchy": "^3.1.7",
-    "@types/d3-shape": "^3.1.8",
+    "@types/dagre": "^0.7.54",
     "@types/node": "^25.2.3",
     "@types/react": "^19.2.14",
     "@types/react-dom": "^19.2.3",
@@ -76,6 +75,7 @@
     "@ai-sdk/mistral": "^3.0.21",
     "@ai-sdk/openai": "^3.0.37",
     "@braintree/sanitize-url": "^7.1.2",
+    "@dagrejs/dagre": "^2.0.4",
     "@floating-ui/dom": "^1.7.5",
     "@highlightjs/cdn-assets": "^11.11.1",
     "@libsql/client": "^0.17.0",
@@ -97,8 +97,6 @@
     "ai": "^6.0.105",
     "chokidar": "^5.0.0",
     "d3-cloud": "^1.2.8",
-    "d3-hierarchy": "^3.1.2",
-    "d3-shape": "^3.2.0",
     "date-fns": "^4.1.0",
     "drizzle-orm": "^0.45.1",
     "dropbox": "^10.34.0",