perf(session): reuse immutable event snapshots

apps/cli/tests/profiles/headless/tests/coding-task.e2e.ts

@@ -67,7 +67,7 @@ describe.skipIf(!process.env.DEEPSEEK_API_KEY)('coding task: fix a failing test
     await waitForIdle(ctx, agent)
 
     // The agent claims success…
-    const summary = finalText([...agent.session.snapshotEvents()]).toLowerCase()
+    const summary = finalText(agent.session.snapshotEvents()).toLowerCase()
     expect(summary.length).toBeGreaterThan(0)
 
     // …and the world agrees: the test passes when WE run it, and the test

apps/cli/tests/profiles/headless/tests/compaction.e2e.ts

@@ -56,7 +56,7 @@ describe.skipIf(!process.env.DEEPSEEK_API_KEY)('compaction: a long session compa
       }], source: { kind: 'user' } }))
     await waitForIdle(ctx, agent)
 
-    const events = [...agent.session.snapshotEvents()]
+    const events = agent.session.snapshotEvents()
 
     // A compaction ran: the start…end bracket landed in the real log.
     const starts = events.filter(e => e.type === 'compaction/start')

apps/cli/tests/profiles/headless/tests/full-loop.e2e.ts

@@ -34,7 +34,7 @@ describe.skipIf(!process.env.DEEPSEEK_API_KEY)('full loop: real model + real bas
     agent.followup(createUserMessage({ content: [{ type: 'text', text: 'Run `echo e2e-ok` with the bash tool and tell me its exact output.' }], source: { kind: 'user' } }))
     await waitForIdle(ctx, agent)
 
-    const events = [...agent.session.snapshotEvents()]
+    const events = agent.session.snapshotEvents()
     const calls = events.filter(event => event.type === 'tool/call')
     expect(calls.length).toBeGreaterThan(0)
     expect(calls.some(event => event.data.name === 'bash')).toBe(true)

apps/cli/tests/profiles/headless/tests/harness.ts

@@ -96,7 +96,7 @@ export function waitForIdle(ctx: Context, agent: Agent): Promise<void> {
   })
 }
 
-export function finalText(events: SessionEvent[]): string {
+export function finalText(events: readonly SessionEvent[]): string {
   const message = events.findLast(event => event.type === 'assistant/message')
   if (message?.type !== 'assistant/message') return ''
   return message.data.message.content

apps/cli/tests/profiles/headless/tests/ptc.e2e.ts

@@ -366,7 +366,7 @@ describe.skipIf(!process.env.DEEPSEEK_API_KEY)('PTC mode: real model writes a pr
         + 'and return only the joined string.',
       }], source: { kind: 'user' } }))
     await waitForIdle(ctx, agent)
-    const events: SessionEvent[] = [...agent.session.snapshotEvents()]
+    const events: readonly SessionEvent[] = agent.session.snapshotEvents()
 
     // The wire contract: every request this session made offered EXACTLY ONE
     // tool — run_code (the logged header snapshots the assembled list).
@@ -418,7 +418,7 @@ describe.skipIf(!process.env.DEEPSEEK_API_KEY)('PTC mode: real model writes a pr
       }], source: { kind: 'user' } }))
     await waitForIdle(ctx, handle.agent)
 
-    const events: SessionEvent[] = [...handle.agent.session.snapshotEvents()]
+    const events: readonly SessionEvent[] = handle.agent.session.snapshotEvents()
     const dispatch = events.find(event => event.type === 'tool/code-dispatch' && event.data.name === 'read')
     const outerResult = events.find(event => event.type === 'tool/result')
     const workspaceContext = await vi.waitFor(() => {

apps/cli/tests/profiles/headless/tests/resume.e2e.ts

@@ -63,6 +63,6 @@ describe.skipIf(!process.env.DEEPSEEK_API_KEY)('resume: continue a persisted ses
     await waitForIdle(ctx, resumed)
 
     // The model recalls it — only possible from the resumed history.
-    expect(finalText([...resumed.session.snapshotEvents()])).toContain(SECRET)
+    expect(finalText(resumed.session.snapshotEvents())).toContain(SECRET)
   }, 180_000)
 })

apps/cli/tests/profiles/headless/tests/todo-write.e2e.ts

@@ -37,7 +37,7 @@ describe.skipIf(!process.env.DEEPSEEK_API_KEY)('todo_write: real model records a
       + 'Send all three in one todo_write call, then reply with the single word DONE.' }], source: { kind: 'user' } }))
     await waitForIdle(ctx, agent)
 
-    const events = [...agent.session.snapshotEvents()]
+    const events = agent.session.snapshotEvents()
 
     // The model actually called the tool.
     const calls = events.filter(event => event.type === 'tool/call')