Release orchard v0.13.1

[czarcas7ic]

Patch release. Promotes the post-0.13.0 entries in CHANGELOG.md (the NoteValue::ZERO const, the unstable-voting-circuits SpendAuthG fixed-base additions, and the related visibility widenings) into a new 0.13.1 section. All changes are backwards-compatible. The unstable-voting-circuits APIs are explicitly outside the crate's semver guarantees.

[ebfull]

orchard 0.13.0 was tagged based on the merge of #493 (081c2ac), which means that the 0.13.0 release did not include anything from #488. But the CHANGELOG.md here (git diff 0.13.0..adam/release-0.13.1) places the changes involved in #488 under the 0.13.0 section of the changelog, rather than the 0.13.1 section, since the merge strategy resolved incorrectly.

This release PR needs to update the CHANGELOG.md so that it consolidates the changes for 0.13.1 in the correct section. Here's a proposed rewrite:

--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,35 +10,10 @@ and this project adheres to Rust's notion of
 ## [0.13.1] - 2026-04-27
 
 ### Added
-- `orchard::value::NoteValue::ZERO`, a `const NoteValue` equal to zero.
-
-### Changed
-- The following APIs have changed or been made available behind the
-  `unstable-voting-circuits` feature flag, and are not covered by the
-  crate's semver stability guarantees and may change in any future
-  release:
-  - `orchard::constants::OrchardFixedBases` has been reorganized to wrap
-    two new fixed-base enums, each adding `SpendAuthG` as a supported
-    generator alongside the existing `NullifierK` / `ValueCommitV`
-    generators. Existing `From<NullifierK>` and `From<ValueCommitV>`
-    conversions to `OrchardFixedBases` are preserved.
-  - `orchard::constants::OrchardBaseFieldBases`: fixed bases for scalar
-    multiplication by a base-field scalar.
-  - `orchard::constants::OrchardShortScalarBases`: fixed bases for scalar
-    multiplication by a short signed scalar.
-
-## [0.13.0] - 2026-04-22
-
-### Added
-- `orchard::primitives::redpallas::VerificationKey<T>::is_identity`, which
-  returns `true` if the verification key is the identity `pallas::Point`.
-- `orchard::primitives::redpallas::testing::arb_valid_spendauth_keypair`
-  (under the `test-dependencies` feature): a uniformly-distributed valid
-  `(rsk, rk)` key pair with non-identity `rk`.
 - `orchard::{L_ORCHARD_BASE, L_ORCHARD_SCALAR, L_VALUE}`, the bit-length
   parameters of the Orchard base field, scalar field, and value encoding
   as defined in the Zcash protocol specification.
-- `orchard::value::NoteValue::zero`, equivalent to `NoteValue::from_raw(0)`.
+- `orchard::value::NoteValue::ZERO`, a `const NoteValue` equal to zero.
 - The following modules and APIs are available behind the
   `unstable-voting-circuits` feature flag to support downstream
   voting-circuit development. These temporary APIs are not covered by the
@@ -54,6 +29,15 @@ and this project adheres to Rust's notion of
     `AddChip::{configure, construct}`,
     `CommitIvkChip::{configure, construct}`,
     `NoteCommitChip::{configure, construct}`.
+  - Fixed bases: `orchard::constants::OrchardFixedBases` wraps two
+    fixed-base enums, each supporting `SpendAuthG` alongside the
+    existing `NullifierK` / `ValueCommitV` generators; `From<NullifierK>`
+    and `From<ValueCommitV>` conversions to `OrchardFixedBases` are
+    provided. The wrapped enums are exposed as
+    `orchard::constants::OrchardBaseFieldBases` (fixed bases for scalar
+    multiplication by a base-field scalar) and
+    `orchard::constants::OrchardShortScalarBases` (fixed bases for
+    scalar multiplication by a short signed scalar).
   - Key, note, tree, and value APIs: `SpendingKey::random`,
     `SpendAuthorizingKey::derive_inner`, `NullifierDerivingKey` and
     `CommitIvkRandomness` and their `inner` methods,
@@ -66,6 +50,15 @@ and this project adheres to Rust's notion of
     `NonIdentityPallasPoint` and `NonIdentityPallasPoint::from_bytes`,
     `MerklePath::dummy`, and `MerkleHashOrchard::inner`.
 
+## [0.13.0] - 2026-04-22
+
+### Added
+- `orchard::primitives::redpallas::VerificationKey<T>::is_identity`, which
+  returns `true` if the verification key is the identity `pallas::Point`.
+- `orchard::primitives::redpallas::testing::arb_valid_spendauth_keypair`
+  (under the `test-dependencies` feature): a uniformly-distributed valid
+  `(rsk, rk)` key pair with non-identity `rk`.
+
 ### Changed
 - MSRV is now 1.85.1
 - Migrated from yanked `core2` library to `corez`

[ebfull]

I just noticed that a few of the crates in Cargo.lock are pinned to versions that were yanked on crates.io, which causes warnings when publishing the crate. We might as well leave behind a better world for our children:

cargo update -p shardtree@0.6.0 --precise 0.6.1
cargo update -p ahash@0.8.3 --precise 0.8.4
cargo update -p bytemuck@1.14.0 --precise 1.25.0
cargo update -p rgb@0.8.36 --precise 0.8.48

These are all minimal bumps of (transitive) dev-dependencies.

[nuttycom]

utACK f8915bc

[ebfull]

0.13.1 tagged and released on crates.io.