fix(web): address session fork review findings

apps/web/tests/snapshots/message-actions/fork.expected.md

@@ -0,0 +1,9 @@
+- tree "Sessions":
+  - treeitem "Ungrouped 2 sessions" [expanded]:
+    - img
+    - text: Ungrouped 2 sessions
+  - treeitem "Collapse Use the read tool twice 1min" [expanded]:
+    - button "Collapse":
+      - img
+    - text: Use the read tool twice 1min
+  - treeitem "Use the read tool twice now" [selected]

apps/web/tests/snapshots/message-actions/ui.expected.md

@@ -31,7 +31,7 @@
   - img
 - button "在新对话中分支":
   - img
-- text: {{clock}}
+- text: {{clock}} cache hit 98% · 15,962 tokens · 1 turns · 2 steps
 - textbox "Message the agent"
 - button "Add attachment":
   - img
@@ -41,4 +41,3 @@
   - text: deepseek-v4-flash
   - img
 - button "Send message" [disabled]
-- text: 1 turns · 2 steps Tool call {{duration}} Cache hit 98% Input 15.8K tok · Output 135 tok