Bump the generated-gates lesson to Seen 3x (PR #177 packaging failure) #206

The 2026-10-17 failure digest found that an intermediate push of PR #177 failed the package job (run 39028263159: patches/pin check) before its final green tip — the same class as #94 and #99.

The LESSONS.md lesson "2026-10-15 — Generated gates run after the last edit" is therefore at its third sighting and, being ≥3 calendar days old, is now promotion-eligible into docs/code-standards.md (merge-gate section).

This issue tracks the Seen bump only; promotion stays with the maintainer.