apply_patch stores deleted binary in session history, permanently exceeding CAPI 5 MB limit

### Describe the bug

When `apply_patch` deletes a large binary file, its `tool.execution_complete` event stores the entire deleted binary as a textual diff in `result.detailedContent`.

This result remains in conversation history. Subsequent requests exceed CAPI Responses' 5 MB limit, and `/compact` fails for the same reason, leaving the session unrecoverable through the CLI.

### Affected configuration

- GitHub Copilot CLI 1.0.71-0
- Linux
- Model: GPT-5.6 Sol (`gpt-5.6-sol`)
- Context window: 1.1M
- Reasoning effort: high
- Interactive session later resumed with `copilot --resume=`

The model, context-window size, and reasoning effort may affect when compaction runs, but the persisted binary tool output appears to be the direct cause of the 5 MB transport failure.

### Observed sequence

1. Copilot used `apply_patch` to delete a large ELF executable.
2. The persisted event contained:
- `result.detailedContent`: 22,810,594 characters
- Serialized JSONL record: 72,155,553 bytes
- Tool telemetry: 111,879 removed lines
3. `events.jsonl` grew to 118,622,622 bytes.
4. Further requests failed with:

> The request is too large to send through CAPI Responses. Try shortening the conversation or prompt. (5.0 MB request; 5.0 MB limit)

5. Automatic/manual compaction failed with the same error.

### Expected behavior

Binary content should not be persisted as a textual patch. The CLI should retain deletion metadata while omitting or capping oversized `detailedContent`.

After a request-size failure, oversized tool output should be evicted so compaction can recover the session.

### Workaround and root-cause confirmation

After backing up the session, I replaced the oversized `detailedContent` with a short marker. This reduced the event log from 118.6 MB to 46.5 MB and eliminated the CAPI request-size failure.

### Related issues

This resembles #3767, but that issue covered inline attachments and was fixed in v1.0.62. This report concerns persisted `apply_patch` output in v1.0.71.

The session also developed malformed JSONL records that prevented resume, reported separately in #4098. The shared root cause is not proven, although the unusually large write may have widened the failure window.

I have not attached `events.jsonl` because it contains conversation and tool history.

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Investigated and filed with assistance from GitHub Copilot CLI.

Verfolge die Ausgabe von apply_patch durch das Ereignis tool.execution_complete, insbesondere result.detailedContent, bevor sie in events.jsonl geschrieben und in CAPI Responses-Anfragen aufgenommen wird. Reproduziere dies mit einer gelöschten großen Binärdatei und führe /compact aus. Als erledigt gilt die Aufgabe, wenn die Löschmetadaten erhalten bleiben, ohne übergroße Textinhalte zu persistieren, und die Komprimierung sich nach einem Fehler aufgrund der Anfragegröße erholen kann.

Vom Indexierungsmodell aus dem Issue-Text verfasst.