Bring main onto the line this project actually ships

main had drifted to a history with no ancestor in common with the tree we
build and deploy. It sat at be63e83 (2026-08-09) with 28 commits; the shipped
line, deploy/soak-2026-08-21, had 383. The two shared nothing -- git
merge-base returns no result at all -- so anyone cloning this repository
landed on a default branch that was neither current nor related to the
running node.

The 28 commits on main were audited before this merge: every one is already
present in the tree by content, including the two that are hardest to see
because they were rewritten afterwards -- the payout reorg-safety work
(PayoutBlockStillOnChain, since evolved to re-check on every retry rather
than once at maturity) and the nostr relay certificate verification
(SSL_set1_host, now with a Windows root-store path). Nothing on main is lost
by this merge.

Recorded as a merge rather than a force-push: main only ever moves forward,
its old history stays reachable as the first parent, and this is revertible.
The tree is taken wholesale from the merged branch, so main's content is now
exactly what was built and tested.

What this brings onto main:

- compactblock: BIP152-style compact block relay ported from upstream 1.2.23,
  primitives and unit test only, with the RAND_bytes failure path closed and
  the reconstruction allocation bounded.
- upstream/main 17741d9: isolated testnet parameters and genesis, optional
  2 MB large pages for RandomX. Mainnet genesis verified byte-identical
  through upstream's BuildGenesisBlock() refactor.
- deploy: every image built on bookworm so binaries run on Debian 12, and the
  container build now honours the RandomX and libsecp256k1 pins it had been
  silently ignoring since before 1.2.15.

Gates at this tree: 15/15 selftests, compactblock's 17 checks, consensus
constants unchanged against e4f898c apart from the pre-existing
MAX_BLOCK_SIZE_GEN, mainnet genesis intact, money-log check ok.

1 files changed, 61 insertions, 0 deletions

diff --git a/docs/utxo-proofs.md b/docs/utxo-proofs.md
new file mode 100644
index 0000000..4947c3c
--- /dev/null
+++ b/docs/utxo-proofs.md
@@ -0,0 +1,61 @@
+# Bitflash UTXO inclusion proofs
+
+`scripts/prove-utxo.py` creates a deterministic inclusion proof for one
+currently unspent output. `scripts/verify-utxo-proof.py` verifies that proof
+against the UTXO root produced by `scripts/verify-utxo-set.py`.
+
+This is intentionally outside consensus. It turns the audit root into something
+useful for a specific coin without changing what nodes accept.
+
+## Create A Proof
+
+Use an unspent output in `txid:vout` form:
+
+```bash
+python3 scripts/prove-utxo.py TXID:VOUT --out utxo-proof.json --json
+```
+
+The proof contains:
+
+- the target UTXO;
+- its sorted leaf index;
+- the leaf hash;
+- the Merkle sibling path;
+- the UTXO root and chain tip used to create it.
+
+It does not contain the full UTXO set.
+
+## Verify A Proof
+
+Verify against the root embedded in the proof:
+
+```bash
+python3 scripts/verify-utxo-proof.py utxo-proof.json
+```
+
+Or verify against a root copied from another machine, dashboard, block explorer,
+or future node export:
+
+```bash
+python3 scripts/verify-utxo-proof.py utxo-proof.json \
+  --root ROOT_FROM_REPORT_OR_EXPORT
+```
+
+The verifier does not need local `blk*.dat` files. It only needs the proof and
+the expected root.
+
+## Scope
+
+This first proof format supports inclusion only. Absence and range proofs are
+left for a later design because they require a more careful commitment scheme
+and are easier to get subtly wrong.
+
+The proof uses the exact same leaf and node domains as the UTXO commitment:
+
+```text
+BTFUTXO1
+BTFNODE1
+```
+
+That keeps the verifier language-neutral and gives future implementations a
+small, stable target.