diff --git a/web/package.json b/web/package.json
index 2521c62..465f417 100644
--- a/web/package.json
+++ b/web/package.json
@@ -50,6 +50,7 @@
     "framer-motion": "^12.6.5",
     "hast": "^1.0.0",
     "highlight.js": "^11.11.1",
+    "immer": "^10.1.1",
     "katex": "^0.16.21",
     "lowlight": "^3.3.0",
     "lru-cache": "^11.1.0",
diff --git a/web/pnpm-lock.yaml b/web/pnpm-lock.yaml
index 1f60710..3c76ce3 100644
--- a/web/pnpm-lock.yaml
+++ b/web/pnpm-lock.yaml
@@ -85,7 +85,7 @@ importers:
         version: 2.11.7(@tiptap/core@2.11.7(@tiptap/pm@2.11.7))(@tiptap/pm@2.11.7)(react-dom@19.1.0(react@19.1.0))(react@19.1.0)
       '@xyflow/react':
         specifier: ^12.6.0
-        version: 12.6.0(@types/react@19.1.2)(react-dom@19.1.0(react@19.1.0))(react@19.1.0)
+        version: 12.6.0(@types/react@19.1.2)(immer@10.1.1)(react-dom@19.1.0(react@19.1.0))(react@19.1.0)
       best-effort-json-parser:
         specifier: ^1.1.3
         version: 1.1.3
@@ -107,6 +107,9 @@ importers:
       highlight.js:
         specifier: ^11.11.1
         version: 11.11.1
+      immer:
+        specifier: ^10.1.1
+        version: 10.1.1
       katex:
         specifier: ^0.16.21
         version: 0.16.21
@@ -133,7 +136,7 @@ importers:
         version: 0.4.6(react-dom@19.1.0(react@19.1.0))(react@19.1.0)
       novel:
         specifier: ^1.0.2
-        version: 1.0.2(@tiptap/extension-code-block@2.11.7(@tiptap/core@2.11.7(@tiptap/pm@2.11.7))(@tiptap/pm@2.11.7))(@types/react-dom@19.1.1(@types/react@19.1.2))(@types/react@19.1.2)(highlight.js@11.11.1)(lowlight@3.3.0)(react-dom@19.1.0(react@19.1.0))(react@19.1.0)
+        version: 1.0.2(@tiptap/extension-code-block@2.11.7(@tiptap/core@2.11.7(@tiptap/pm@2.11.7))(@tiptap/pm@2.11.7))(@types/react-dom@19.1.1(@types/react@19.1.2))(@types/react@19.1.2)(highlight.js@11.11.1)(immer@10.1.1)(lowlight@3.3.0)(react-dom@19.1.0(react@19.1.0))(react@19.1.0)
       react:
         specifier: ^19.0.0
         version: 19.1.0
@@ -184,7 +187,7 @@ importers:
         version: 3.24.3
       zustand:
         specifier: ^5.0.3
-        version: 5.0.3(@types/react@19.1.2)(react@19.1.0)(use-sync-external-store@1.5.0(react@19.1.0))
+        version: 5.0.3(@types/react@19.1.2)(immer@10.1.1)(react@19.1.0)(use-sync-external-store@1.5.0(react@19.1.0))
     devDependencies:
       '@eslint/eslintrc':
         specifier: ^3.3.1
@@ -2639,6 +2642,9 @@ packages:
     resolution: {integrity: sha512-hsBTNUqQTDwkWtcdYI2i06Y/nUBEsNEDJKjWdigLvegy8kDuJAS8uRlpkkcQpyEXL0Z/pjDy5HBmMjRCJ2gq+g==}
     engines: {node: '>= 4'}
 
+  immer@10.1.1:
+    resolution: {integrity: sha512-s2MPrmjovJcoMaHtx6K11Ra7oD05NT97w1IC5zpMkT6Atjr7H8LjaDd81iIxUYpMKSRRNMJE703M1Fhr/TctHw==}
+
   import-fresh@3.3.1:
     resolution: {integrity: sha512-TR3KfrTZTYLPB6jUjfx6MF9WcWrHL9su5TObK4ZkYgBdWKPOFoSoQIdEuTuR82pmtxH2spWG9h6etwfr1pLBqQ==}
     engines: {node: '>=6'}
@@ -5695,13 +5701,13 @@ snapshots:
 
   '@xtuc/long@4.2.2': {}
 
-  '@xyflow/react@12.6.0(@types/react@19.1.2)(react-dom@19.1.0(react@19.1.0))(react@19.1.0)':
+  '@xyflow/react@12.6.0(@types/react@19.1.2)(immer@10.1.1)(react-dom@19.1.0(react@19.1.0))(react@19.1.0)':
     dependencies:
       '@xyflow/system': 0.0.57
       classcat: 5.0.5
       react: 19.1.0
       react-dom: 19.1.0(react@19.1.0)
-      zustand: 4.5.6(@types/react@19.1.2)(react@19.1.0)
+      zustand: 4.5.6(@types/react@19.1.2)(immer@10.1.1)(react@19.1.0)
     transitivePeerDependencies:
       - '@types/react'
       - immer
@@ -6688,6 +6694,8 @@ snapshots:
 
   ignore@5.3.2: {}
 
+  immer@10.1.1: {}
+
   import-fresh@3.3.1:
     dependencies:
       parent-module: 1.0.1
@@ -7481,7 +7489,7 @@ snapshots:
 
   node-releases@2.0.19: {}
 
-  novel@1.0.2(@tiptap/extension-code-block@2.11.7(@tiptap/core@2.11.7(@tiptap/pm@2.11.7))(@tiptap/pm@2.11.7))(@types/react-dom@19.1.1(@types/react@19.1.2))(@types/react@19.1.2)(highlight.js@11.11.1)(lowlight@3.3.0)(react-dom@19.1.0(react@19.1.0))(react@19.1.0):
+  novel@1.0.2(@tiptap/extension-code-block@2.11.7(@tiptap/core@2.11.7(@tiptap/pm@2.11.7))(@tiptap/pm@2.11.7))(@types/react-dom@19.1.1(@types/react@19.1.2))(@types/react@19.1.2)(highlight.js@11.11.1)(immer@10.1.1)(lowlight@3.3.0)(react-dom@19.1.0(react@19.1.0))(react@19.1.0):
     dependencies:
       '@radix-ui/react-slot': 1.2.0(@types/react@19.1.2)(react@19.1.0)
       '@tiptap/core': 2.11.7(@tiptap/pm@2.11.7)
@@ -7512,7 +7520,7 @@ snapshots:
       react-tweet: 3.2.2(react-dom@19.1.0(react@19.1.0))(react@19.1.0)
       tippy.js: 6.3.7
       tiptap-extension-global-drag-handle: 0.1.18
-      tunnel-rat: 0.1.2(@types/react@19.1.2)(react@19.1.0)
+      tunnel-rat: 0.1.2(@types/react@19.1.2)(immer@10.1.1)(react@19.1.0)
     transitivePeerDependencies:
       - '@tiptap/extension-code-block'
       - '@types/react'
@@ -8341,9 +8349,9 @@ snapshots:
 
   tslib@2.8.1: {}
 
-  tunnel-rat@0.1.2(@types/react@19.1.2)(react@19.1.0):
+  tunnel-rat@0.1.2(@types/react@19.1.2)(immer@10.1.1)(react@19.1.0):
     dependencies:
-      zustand: 4.5.6(@types/react@19.1.2)(react@19.1.0)
+      zustand: 4.5.6(@types/react@19.1.2)(immer@10.1.1)(react@19.1.0)
     transitivePeerDependencies:
       - '@types/react'
       - immer
@@ -8623,16 +8631,18 @@ snapshots:
 
   zod@3.24.3: {}
 
-  zustand@4.5.6(@types/react@19.1.2)(react@19.1.0):
+  zustand@4.5.6(@types/react@19.1.2)(immer@10.1.1)(react@19.1.0):
     dependencies:
       use-sync-external-store: 1.5.0(react@19.1.0)
     optionalDependencies:
       '@types/react': 19.1.2
+      immer: 10.1.1
       react: 19.1.0
 
-  zustand@5.0.3(@types/react@19.1.2)(react@19.1.0)(use-sync-external-store@1.5.0(react@19.1.0)):
+  zustand@5.0.3(@types/react@19.1.2)(immer@10.1.1)(react@19.1.0)(use-sync-external-store@1.5.0(react@19.1.0)):
     optionalDependencies:
       '@types/react': 19.1.2
+      immer: 10.1.1
       react: 19.1.0
       use-sync-external-store: 1.5.0(react@19.1.0)