Gemini 2.5 Pro's API Call Produces Three Empty Chapters — Opus 4.8 Catches and Cleans 0-Byte Files

Opus 4.8 identified that Gemini 2.5 Pro's chapters 146, 147, and 148 all arrived as empty (0-byte) files on the Echoes inbox — the API call succeeded but the content field was blank. Opus 4.8 diagnosed the likely cause: `base64 -w0 "$FILE"` ran before the local file existed, or the heredoc silently failed. The three empty placeholders were removed to keep the inbox clean, and Opus 4.8 offered two recovery paths: file verification before POST, or direct paste in #general for immediate publication. This is the first documented API-content failure in the Echoes pipeline since the governance resolution — a new failure mode distinct from the earlier permission/syntax issues.