fix: close peer socket listener handoff window

CodeRabbit and Claude review found that documenting caller-owned raw socket errors still left a Promise handoff window and a stale timeout-listener risk. The peer connection API now requires a caller error handler and installs it before resolving, while cleanup removes internal error and timeout listeners on every path.

Constraint: Keep the fix precise to PR #375 review feedback and avoid warning suppression or fallback behavior.
Rejected: Leave the behavior documented only | still permits an unhandled socket error window between resolve and caller listener attachment.
Rejected: Keep a no-op internal error listener | would silently swallow caller-owned socket errors.
Confidence: high
Scope-risk: narrow
Directive: Do not add raw connectToPeer callers without providing a real onSocketError handler and capability handshake.
Tested: bun test src/utils/__tests__/udsMessaging.test.ts src/services/AgentSummary/__tests__/agentSummary.test.ts
Tested: bunx tsc --noEmit --pretty false
Tested: bun run lint
Tested: bun run test:all
Tested: bun test --coverage --coverage-reporter lcov --coverage-dir coverage
Tested: bun run build
Tested: bun run build:vite
Tested: bun audit
Not-tested: Manual external ACP peer runtime beyond repository tests.

src/services/AgentSummary/__tests__/agentSummary.test.ts

@@ -161,7 +161,9 @@ describe('startAgentSummarization', () => {
 
     expect(forkCalls).toEqual([])
     expect(updateCalls).toEqual([])
-    expectDebugLogContaining('no bounded context available')
+    expectDebugLogContaining(
+      '[AgentSummary] Skipping summary for task-1: no bounded context available',
+    )
   })
 
   test('skips summarization before building context when transcript is too short', async () => {
@@ -173,7 +175,9 @@ describe('startAgentSummarization', () => {
 
     expect(forkCalls).toEqual([])
     expect(updateCalls).toEqual([])
-    expectDebugLogContaining('not enough messages (2)')
+    expectDebugLogContaining(
+      '[AgentSummary] Skipping summary for task-1: not enough messages (2)',
+    )
   })
 
   test('skips and reschedules while poor mode is active', async () => {
@@ -188,7 +192,7 @@ describe('startAgentSummarization', () => {
 
     expect(forkCalls).toEqual([])
     expect(updateCalls).toEqual([])
-    expectDebugLogContaining('poor mode active')
+    expectDebugLogContaining('[AgentSummary] Skipping summary — poor mode active')
     expect(scheduledCount).toBe(initialScheduledCount + 1)
     expect(lastTimerHandle).not.toBe(initialTimerHandle)
   })
@@ -218,7 +222,7 @@ describe('startAgentSummarization', () => {
 
     handle.stop()
 
-    expectDebugLogContaining('Stopping summarization for task-1')
+    expectDebugLogContaining('[AgentSummary] Stopping summarization for task-1')
     expect(clearedHandles).toEqual([pendingHandle])
   })
 })