docs: seed docs/proof-debt.md (zero-debt invariant) per trusted-base policy (#26)

## Summary
- Adds `docs/proof-debt.md` declaring this repo's zero-soundness-debt
invariant.
- Verified: every syntactic `believe_me` / `assert_total` / `postulate`
match in source is inside a docstring explicitly stating the file does
NOT use that construct.
- Closes part of the [estate trusted-base reduction
policy](hyperpolymath/standards#203) follow-up
(P1 seed).

## Effect
Future PRs that introduce real escape hatches will be caught by
[`check-trusted-base.sh`](hyperpolymath/standards#211)
and must annotate inline OR enumerate here.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

Author: hyperpolymath

docs/proof-debt.md

@@ -0,0 +1,57 @@
+<!--
+SPDX-License-Identifier: MPL-2.0
+SPDX-FileCopyrightText: 2026 Jonathan D.A. Jewell (hyperpolymath)
+-->
+
+# Proof Debt — snifs
+
+**Schema**: [hyperpolymath/standards `TRUSTED-BASE-REDUCTION-POLICY.adoc`](https://github.com/hyperpolymath/standards/blob/main/docs/TRUSTED-BASE-REDUCTION-POLICY.adoc) (standards#203).
+
+## Current state
+
+**Zero soundness-relevant escape hatches** in this repo as of 2026-05-26.
+
+Verified by `scripts/check-trusted-base.sh` from
+[hyperpolymath/standards](https://github.com/hyperpolymath/standards) —
+all matches found by syntactic scan were inside docstrings explicitly
+stating the file does NOT use `believe_me` / `assert_total` /
+`postulate` / `sorry` / `Admitted` (the "no escape hatches"
+discipline pattern).
+
+## (a) DISCHARGED in this repo
+
+*(None — never any to discharge.)*
+
+## (b) BUDGETED — tested with a refutation budget
+
+*(None.)*
+
+## (c) NECESSARY AXIOM
+
+*(None.)*
+
+## (d) DEBT — actively to be closed
+
+*(None.)*
+
+## Preservation contract
+
+This file exists to assert the **zero-debt invariant** for the
+`scripts/check-trusted-base.sh` CI gate (standards#211). Any future PR
+that introduces a soundness-relevant escape hatch MUST either:
+
+1. annotate the call site with a leading `TRUSTED:` / `AXIOM:`
+   comment, OR
+2. add an entry to this file under §(b) / §(c) / §(d).
+
+PRs that introduce un-annotated escape hatches will fail CI.
+
+## Companion documents
+
+- [standards#195](https://github.com/hyperpolymath/standards/pull/195) — estate proof-debt audit.
+- [standards#203](https://github.com/hyperpolymath/standards/pull/203) — trusted-base reduction policy (the schema this file follows).
+- [standards#211](https://github.com/hyperpolymath/standards/pull/211) — `check-trusted-base.sh` CI enforcement.
+
+---
+
+🤖 Initial seed by Claude Code, 2026-05-26.