When hit max_output_tokens, some events are not emitted and logged

When the AI's output is truncated because it exceeds `max_output_tokens` and a subsequent request is made, both the current response and the next "continue" request are lost.

This happens in BYOK usage. I use the custom provider and it provides `65536` `max_output_tokens`. So it easily triggered this bug.

See this `events.jsonl` below (input and output is ommited for privacy):

```jsonl
{"type":"session.start","data":{"sessionId":"summary-qq-group-957302634-1788584545","version":1,"producer":"copilot-agent","copilotVersion":"0.0.0","startTime":"2026-09-05T05:02:26.005Z","selectedModel":"deepseek-v4-flash","reasoningEffort":"high","contextTier":null,"context":{"cwd":"/home/cola/Softwares/kanade-bot"},"remoteSteerable":false,"alreadyInUse":false},"id":"3e23bf11-4b01-4b8a-bc43-ad9b7d007c69","timestamp":"2026-09-05T05:02:26.024Z","parentId":null}
{"type":"user.message","data":{"content":"...","transformedContent":"...","messageId":"33fe414d-6631-449a-a351-3a34b2c2b68d","supportedNativeDocumentMimeTypes":[],"delivery":"idle","interactionId":"9596a41f-2bfc-4191-998c-740b2e30caec","turnId":"0","parentAgentTaskId":"65b27352-d09e-4c72-956b-b69594366d8c"},"id":"f56f57fc-8c67-4bd2-a372-cfb61f2c4109","timestamp":"2026-09-05T05:02:29.423Z","parentId":"3e23bf11-4b01-4b8a-bc43-ad9b7d007c69"}
{"type":"system.message","data":{"role":"system","content":"...","interactionId":"9596a41f-2bfc-4191-998c-740b2e30caec"},"id":"a33407ed-4a7b-4feb-ad75-83d6b0eac50b","timestamp":"2026-09-05T05:02:29.445Z","parentId":"f56f57fc-8c67-4bd2-a372-cfb61f2c4109"}
{"type":"assistant.turn_start","data":{"turnId":"0","interactionId":"9596a41f-2bfc-4191-998c-740b2e30caec"},"id":"5583fe72-b633-44ea-a183-7ac781d075d2","timestamp":"2026-09-05T05:02:29.458Z","parentId":"a33407ed-4a7b-4feb-ad75-83d6b0eac50b"}
{"type":"assistant.turn_end","data":{"turnId":"0"},"id":"5df48ed1-fe69-4ffe-8645-f0fa2545ef14","timestamp":"2026-09-05T05:03:40.349Z","parentId":"5583fe72-b633-44ea-a183-7ac781d075d2"}
{"type":"assistant.turn_start","data":{"turnId":"1","interactionId":"9596a41f-2bfc-4191-998c-740b2e30caec"},"id":"53c4e5ae-2365-4391-86b3-c39735958279","timestamp":"2026-09-05T05:03:40.349Z","parentId":"5df48ed1-fe69-4ffe-8645-f0fa2545ef14"}
{"type":"assistant.turn_end","data":{"turnId":"1"},"id":"d48f14f2-263b-4990-8d66-f5e858a49b10","timestamp":"2026-09-05T05:04:51.913Z","parentId":"53c4e5ae-2365-4391-86b3-c39735958279"}
{"type":"assistant.turn_start","data":{"turnId":"2","interactionId":"9596a41f-2bfc-4191-998c-740b2e30caec"},"id":"e77c5372-08d4-47ba-b886-5a75ae6a5a6d","timestamp":"2026-09-05T05:04:51.914Z","parentId":"d48f14f2-263b-4990-8d66-f5e858a49b10"}
{"type":"assistant.message","data":{"messageId":"51f06be7-30d8-4d28-b8ae-e8dc1fcc9937","model":"deepseek-v4-flash","content":"（继续）...","toolRequests":[],"interactionId":"9596a41f-2bfc-4191-998c-740b2e30caec","turnId":"2","reasoningText":"Let me continue writing the topic summary. I was in the middle of topic 12. Let me continue from there, then complete the personal image section.","rte":false,"apiCallId":"6197b23f-7420-44dd-8bc4-a032e5784de2"},"id":"7fd35caa-4f74-4365-84d5-c39f7556561a","timestamp":"2026-09-05T05:05:41.237Z","parentId":"e77c5372-08d4-47ba-b886-5a75ae6a5a6d"}
{"type":"assistant.turn_end","data":{"turnId":"2"},"id":"1d7b9c22-2a37-4a73-b54e-f7f398c00f40","timestamp":"2026-09-05T05:05:41.244Z","parentId":"7fd35caa-4f74-4365-84d5-c39f7556561a"}
{"type":"session.shutdown","data":{"shutdownType":"routine","totalPremiumRequests":0,"totalNanoAiu":0,"totalApiDurationMs":190704,"sessionStartTime":1788584546005,"eventsFileSizeBytes":368878,"codeChanges":{"linesAdded":0,"linesRemoved":0,"filesModified":[]},"modelMetrics":{"deepseek-v4-flash":{"requests":{"count":3,"cost":0},"usage":{"inputTokens":234114,"outputTokens":21467,"cacheReadTokens":147456,"cacheWriteTokens":0,"reasoningTokens":14945},"totalNanoAiu":0}},"agentMetrics":{"main":{"totalApiDurationMs":190704,"totalNanoAiu":0.0,"modelMetrics":{"deepseek-v4-flash":{"requests":{"count":3,"cost":0.0},"usage":{"inputTokens":234114,"outputTokens":21467,"cacheReadTokens":147456,"cacheWriteTokens":0,"reasoningTokens":14945},"totalNanoAiu":0.0}}}},"currentModel":"deepseek-v4-flash","currentTokens":81090,"systemTokens":816,"conversationTokens":68907,"toolDefinitionsTokens":11364},"id":"391655ed-981c-4225-b84c-8948504c7bae","timestamp":"2026-09-05T05:05:41.537Z","parentId":"1d7b9c22-2a37-4a73-b54e-f7f398c00f40"}
```

OS: Linux Mint 22.3
Copilot SDK Version: v1.0.13
Copilot CLI Version: v1.0.83 (pinned version)

No files, tests, or entry points are identified. Start by reproducing a BYOK request that reaches max_output_tokens, then trace event emission and logging across the truncated response and subsequent continue request. Done means both responses are present in events.jsonl and are logged consistently.

Written by the indexing model from the issue text.