fix(agent-status): drop identity icon on subagent child rows

The child's agentType carries its NAME (e.g. "pr-reviewer"), which is not
an iconable agent and rendered the unknown "?" glyph. Nesting under the
parent row already conveys identity.

src/renderer/src/components/dashboard/DashboardAgentRow.tsx

@@ -340,8 +340,11 @@ const DashboardAgentRow = React.memo(function DashboardAgentRow({
             on the top row. The sub-rows (tool step, assistant response) are
             about the same agent and do not need the icon repeated next to
             them — keeping the icon only on the prompt row lets the sub-rows
-            indent under the prompt text cleanly. */}
-        {!hideIdentityIcon && (
+            indent under the prompt text cleanly. Subagent child rows carry
+            the child's NAME in agentType (not an iconable agent — it would
+            render the unknown "?" glyph), and nesting under the parent
+            already conveys identity. */}
+        {!hideIdentityIcon && agent.rowSource !== 'subagent' && (
           <span className="inline-flex shrink-0" title={identityTitle}>
             <AgentIcon agent={agentTypeToIconAgent(agent.agentType)} size={14} />
           </span>

src/renderer/src/components/sidebar/worktree-card-compact-agent-row.tsx

@@ -120,6 +120,10 @@ export const CompactAgentRow = React.memo(function CompactAgentRow({
     typeof childAgentCount === 'number' &&
     childAgentCount > 0 &&
     typeof onToggleChildAgents === 'function'
+  // Why: subagent child rows carry the child's NAME (e.g. "pr-reviewer") in
+  // agentType, which is not an iconable agent and would render the unknown
+  // "?" glyph. Nesting under the parent already conveys identity.
+  const hideIcon = hideIdentityIcon || agent.rowSource === 'subagent'
   const dotState = getAgentDotState(agent)
   const primary = getCompactAgentPrimary(agent)
   const isLineageChild = agent.lineage?.depth === 1
@@ -196,7 +200,7 @@ export const CompactAgentRow = React.memo(function CompactAgentRow({
         <span className="size-4 shrink-0" aria-hidden />
       ) : null}
       <AgentStateDot state={dotState} size="sm" />
-      {!hideIdentityIcon && (
+      {!hideIcon && (
         <span className="inline-flex shrink-0" title={formatAgentTypeLabel(agent.agentType)}>
           <AgentIcon agent={agentTypeToIconAgent(agent.agentType)} size={13} />
         </span>