test(mship): update tool-call display title tests for client-derived titles

Display titles now come from the Sim-side name resolver, not the stream's
ui.title/phaseLabel. Update the read lifecycle test to expect the
name-derived title and drop the obsolete phaseLabel-fallback test.

Author: Sg312

apps/sim/lib/copilot/request/handlers/handlers.test.ts

@@ -169,10 +169,7 @@ describe('sse-handlers tool lifecycle', () => {
           executor: MothershipStreamV1ToolExecutor.sim,
           mode: MothershipStreamV1ToolMode.async,
           phase: MothershipStreamV1ToolPhase.call,
-          ui: {
-            title: 'Reading foo.txt',
-            phaseLabel: 'Workspace',
-          },
+          ui: {},
         },
       } satisfies StreamEvent,
       context,
@@ -198,53 +195,16 @@ describe('sse-handlers tool lifecycle', () => {
 
     const updated = context.toolCalls.get('tool-1')
     expect(updated?.status).toBe(MothershipStreamV1ToolOutcome.success)
-    expect(updated?.displayTitle).toBe('Reading foo.txt')
+    // Display titles are derived client-side from the tool name (+args), not the
+    // stream; read with no path resolves to the static "Reading file".
+    expect(updated?.displayTitle).toBe('Reading file')
     expect(updated?.result?.output).toEqual({ ok: true })
     expect(context.contentBlocks.at(0)).toEqual(
       expect.objectContaining({
         type: 'tool_call',
         toolCall: expect.objectContaining({
           id: 'tool-1',
-          displayTitle: 'Reading foo.txt',
-        }),
-      })
-    )
-  })
-
-  it('uses phaseLabel as a display title fallback when no title is provided', async () => {
-    executeTool.mockResolvedValueOnce({ success: true, output: { ok: true } })
-    const onEvent = vi.fn()
-
-    await sseHandlers.tool(
-      {
-        type: MothershipStreamV1EventType.tool,
-        payload: {
-          toolCallId: 'tool-phase-label',
-          toolName: ReadTool.id,
-          arguments: { workflowId: 'workflow-1' },
-          executor: MothershipStreamV1ToolExecutor.sim,
-          mode: MothershipStreamV1ToolMode.async,
-          phase: MothershipStreamV1ToolPhase.call,
-          ui: {
-            phaseLabel: 'Workspace',
-          },
-        },
-      } satisfies StreamEvent,
-      context,
-      execContext,
-      { onEvent, interactive: false, timeout: 1000 }
-    )
-
-    await sleep(0)
-
-    const updated = context.toolCalls.get('tool-phase-label')
-    expect(updated?.displayTitle).toBe('Workspace')
-    expect(context.contentBlocks.at(0)).toEqual(
-      expect.objectContaining({
-        type: 'tool_call',
-        toolCall: expect.objectContaining({
-          id: 'tool-phase-label',
-          displayTitle: 'Workspace',
+          displayTitle: 'Reading file',
         }),
       })
     )