docs(#176): restore the DOC-04 status banner and fix 3 dead ledger links

3661d98 removed the DOC-04 banner from README's "Status" section, which
tools/check-doc-truthing.sh requires. That failure has held the `build` job
red on main since 2026-06-28.

Also repoints three references to `SOUNDNESS-LEDGER.adoc` -- a file that does
not exist -- at docs/SOUNDNESS.adoc.

tools/check-doc-truthing.sh now exits 0.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

Author: hyperpolymath

README.adoc

@@ -23,11 +23,21 @@ delivery mechanism. They _are_ the product.
 
 == Status
 
+[IMPORTANT]
+====
+Authoritative per-feature status lives in
+link:docs/CAPABILITY-MATRIX.adoc[docs/CAPABILITY-MATRIX.adoc]; soundness-hole
+status lives in link:docs/SOUNDNESS.adoc[docs/SOUNDNESS.adoc]. Where this
+README and those documents disagree, *they win* --
+`.machine_readable/descriptiles/STATE.a2ml` mirrors the matrix and does not
+lead it.
+====
+
 Early and experimental. This is *v0.2*: the architecture is settled, the
 implementation and the metatheory are partial and still moving. It is suitable
 for experimentation, teaching, and small sound components -- not yet for
 production. What is proven, what is implemented, and what is still prose are
-stated plainly below and tracked in `SOUNDNESS-LEDGER.adoc`.
+stated plainly below and tracked in link:docs/SOUNDNESS.adoc[docs/SOUNDNESS.adoc].
 
 == What you get
 
@@ -142,7 +152,7 @@ risk here, and it is not yet solved.
 Soundness is *partially mechanised, and honestly tracked.* An initial,
 axiom-free, machine-checked result for code-generation preservation exists
 (Coq/Rocq). A number of residuals remain open; they are recorded -- not hidden
--- in `SOUNDNESS-LEDGER.adoc`, which states for each claim whether it is
+-- in link:docs/SOUNDNESS.adoc[docs/SOUNDNESS.adoc], which states for each claim whether it is
 mechanised or still argued in prose.
 
 The ledger is the source of truth for what currently holds. This README
@@ -192,7 +202,7 @@ totality cut, and a WebAssembly target -- rather than any one ingredient.
 == Documentation
 
 // TODO: link the design notes and the examples directory once locations are stable.
-* Soundness status: `SOUNDNESS-LEDGER.adoc`
+* Soundness status: link:docs/SOUNDNESS.adoc[docs/SOUNDNESS.adoc]
 
 == License