docs: record tech-debt audit findings (2026-05-26) (#12)

Adds docs/tech-debt-2026-05-26.md with this repo's findings from the
estate-wide tech-debt scan: proof debt, licence debt, documentation
debt.

This file records the findings only — it does not close the debt.

Cross-references:
- hyperpolymath/standards#195 (estate proof-debt audit)
- hyperpolymath/standards#196 (estate licence-debt audit)
- hyperpolymath/standards#197 (estate documentation-debt audit)

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: hyperpolymath