[BUG] Grok 4.3 "Unable to apply diff" - Expected '=======' was not found. #186

Problem (one or two sentences)

Grok 4.3 frequently generates malformed or truncated diffs that fail to apply in Zoo Code, producing the error: "Unable to apply diff to file: ... ERROR: Unexpected end of sequence: Expected '=======' was not found."

Context (who is affected and when)
Affects users editing files with Grok 4.3 in Zoo Code's diff/edit mode. Happens during normal code editing tasks.

Reproduction steps

1. Use Grok 4.3 (or similar Grok coder variant) in Zoo Code.
2. Ask it to make changes to a file via diff.
3. The model outputs an incomplete diff missing the expected ======= separator.
4. Zoo Code's apply_diff tool fails with the exact error shown in the attached screenshot.

Expected result
The diff should apply cleanly, or Zoo Code should gracefully handle/fallback on malformed output from the model.

Actual result
Edit fails with "Unable to apply diff" and the sequence error.

Variations tried (optional)

• Retrying the same prompt (sometimes succeeds, often fails again).
• More explicit prompts asking for clean unified diffs.

App Version
v3.54.1

API Provider
xAI / Grok

Model Used
Grok 4.3

Zoo Code Task Links (optional)
(none)

Relevant logs or errors (optional)

Unable to apply diff to file: /home/user/dev/ipall/apps/backup/ipfs-backup/lib/common.sh

<error_details>
ERROR: Unexpected end of sequence: Expected '=======' was not found.
</error_details>