[codex] Add local tool trace toggle (#806)

* test: harden tool approval browser contract

* test: cover tool trace display edge cases

* test: cover resumed tool trace edge cases

* feat: hide tool traces by default

* Add local tool trace toggle

---------

Co-authored-by: Zhicheng Han <zhicheng.han@mathematik.uni-goettingen.de>

packages/client/src/stores/hermes/chat.ts

@@ -136,10 +136,11 @@ async function buildContentBlocks(
 }
 
 function mapHermesMessages(msgs: HermesMessage[]): Message[] {
-  // Filter out assistant messages with empty content
+  // Filter out assistant messages with no display content unless they carry tool call metadata
+  // needed to name later tool result rows when resuming persisted history.
   const filteredMsgs = msgs.filter(m => {
     if (m.role === 'assistant') {
-      return m.content && m.content.trim() !== ''
+      return (m.tool_calls?.length || 0) > 0 || (m.content && m.content.trim() !== '')
     }
     return true
   })
@@ -169,7 +170,7 @@ function mapHermesMessages(msgs: HermesMessage[]): Message[] {
           role: 'tool',
           content: '',
           timestamp: Math.round(msg.timestamp * 1000),
-          toolName: tc.function?.name || 'tool',
+          toolName: tc.function?.name || undefined,
           toolCallId: tc.id,
           toolArgs: tc.function?.arguments || undefined,
           toolStatus: 'done',
@@ -181,7 +182,7 @@ function mapHermesMessages(msgs: HermesMessage[]): Message[] {
     // Tool result messages
     if (msg.role === 'tool') {
       const tcId = msg.tool_call_id || ''
-      const toolName = msg.tool_name || toolNameMap.get(tcId) || 'tool'
+      const toolName = msg.tool_name || toolNameMap.get(tcId) || undefined
       const toolArgs = toolArgsMap.get(tcId) || undefined
       // Extract a short preview from the content
       let preview = ''