diff --git a/.claude/exec-runs/sonnet-197-lint-sweep.md b/.claude/exec-runs/sonnet-197-lint-sweep.md
new file mode 100644
index 00000000..d48f7689
--- /dev/null
+++ b/.claude/exec-runs/sonnet-197-lint-sweep.md
@@ -0,0 +1,42 @@
+# Sonnet clippy lint sweep — rust-toolchain 1.95.0 → 1.97.1
+
+Branch: `claude/x265-x266-plans-review-h9osnl` (shared checkout, no worktree, no commits made).
+
+## Pass 1 — `cargo clippy -p ndarray -- -D warnings` (lib)
+
+3 errors, all `clippy::question_mark` on the identical `match self.<field> { None => return None, Some(ref ix) => ix.clone() }` pattern inside `Iterator::next` impls. Fixed by collapsing to `self.<field>.clone()?`.
+
+- `src/indexes.rs:60` — `IndicesIter::next` — `clippy::question_mark` — replaced 4-line match with `let index = self.index.clone()?;`
+- `src/iterators/mod.rs:491` — `IndexedIter::next` — `clippy::question_mark` — same fix, `self.0.inner.index.clone()?`
+- `src/iterators/mod.rs:667` — `IndexedIterMut::next` — `clippy::question_mark` — same fix, `self.0.inner.index.clone()?`
+
+Re-run: clean (`Finished` in 13.88s).
+
+## Pass 2 — `cargo clippy -p ndarray --tests -- -D warnings`
+
+3 errors, all in `#[cfg(test)]` modules:
+
+- `src/property_mask.rs:426` — `clippy::unusual_byte_groupings` — `0b11111_1000` → `0b1_1111_1000` (regrouped into nibbles per clippy's own suggestion; value unchanged, still asserting the same bit pattern).
+- `src/bitwise.rs:637` — `clippy::identity_op` — `assert_eq!(super::popcount_batch_u64(&words), 64 + 0 + 32)` had a no-op `+ 0`. Replaced with the literal `96` and kept the per-word breakdown as a comment (`// per-word contributions: 64 + 0 + 32`) so the documentational intent survives.
+- `src/palette_codec.rs:810` — `clippy::needless_range_loop` in `test_bedrock_pack_section` — `for i in 0..4096 { states[i] = (i % 4) as u16; }` → `for (i, state) in states.iter_mut().enumerate() { *state = (i % 4) as u16; }`. Purely mechanical (index only used for indexing + the `% 4` value); no semantic change.
+
+Re-run: clean (`Finished` in 36.14s).
+
+## Pass 3 — `cargo fmt -p ndarray`
+
+Applied. Reformatted only the touched hunks (rustfmt collapsed the shortened `next()` bodies and normalized the byte-grouping/comment line spacing). No behavioural diff beyond formatting.
+
+## Nothing skipped
+
+No `src/simd_*.rs` files were touched — none of the flagged lints landed there. No `unsafe` blocks were touched (none of the fixes were near unsafe code). No public API signatures changed.
+
+## Final status
+
+- `cargo clippy -p ndarray -- -D warnings` — **clean**
+- `cargo clippy -p ndarray --tests -- -D warnings` — **clean**
+- `cargo fmt -p ndarray` — **applied**, `git diff --stat`: 5 files changed, 8 insertions(+), 16 deletions(-)
+- No `cargo test` run (disk guard tripped — see below).
+
+## Disk guard note
+
+Free space on `/home/user` dropped from 5.7 GB → 5.3 GB → **4.2 GB** over the course of this run (crossing the 5 GB floor right after the `cargo fmt` invocation, which had itself been preceded by a compliant 5.3 GB check). Per the hard rule I stopped immediately after `cargo fmt` and did **not** run any further cargo invocations (no targeted `cargo test`, no additional clippy passes). All fixes above are comment/mechanical-only changes (`.clone()?` collapse, digit regrouping, literal substitution, `iter_mut().enumerate()`), so behavioural risk is low, but the orchestrator should re-run `cargo test -p ndarray` centrally once disk space is confirmed healthy.
diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index f2fbcab2..fe37abe5 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -21,8 +21,8 @@ env:
   # `LazyLock<Tier>` detection means one binary, all ISAs. Jobs that
   # specifically need a higher target-cpu can opt in via per-job env.
   RUSTFLAGS: "-D warnings"
-  MSRV: 1.95.0
-  BLAS_MSRV: 1.95.0
+  MSRV: 1.97.1
+  BLAS_MSRV: 1.97.1
 
 jobs:
   pass-msrv:
@@ -41,18 +41,18 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        # Pinned to 1.95.0 to match `rust-toolchain.toml`. The workspace
-        # bumped from 1.94.1 → 1.95.0 in commit
+        # Pinned to 1.97.1 to match `rust-toolchain.toml`. The workspace
+        # bumped from 1.94.1 → 1.97.1 in commit
         # https://github.com/AdaWorldAPI/ndarray (this PR) to align with
         # bevy (edition 2024 → 1.95 MSRV) and lance-graph. 1.95 added the
         # `clippy::manual_checked_ops` lint which fires on
         # `impl_owned_array.rs::into_scalar` — fixed in this same PR.
         rust:
-          - "1.95.0"
+          - "1.97.1"
     name: clippy/${{ matrix.rust }}
     steps:
       - uses: actions/checkout@v4
-      - uses: dtolnay/rust-toolchain@1.95.0
+      - uses: dtolnay/rust-toolchain@1.97.1
         with:
           components: clippy
       - uses: Swatinem/rust-cache@v2
@@ -74,10 +74,10 @@ jobs:
     # That state no longer exists; the band-aid is removed in this PR.
     steps:
       - uses: actions/checkout@v4
-      # Stable rustfmt 1.95.0 — pinned in `rust-toolchain.toml`. No
+      # Stable rustfmt 1.97.1 — pinned in `rust-toolchain.toml`. No
       # nightly dependency since rustfmt.toml is stable-clean post-PR
       # #133.
-      - uses: dtolnay/rust-toolchain@1.95.0
+      - uses: dtolnay/rust-toolchain@1.97.1
         with:
           components: rustfmt
       - run: cargo fmt --all --check
@@ -99,7 +99,7 @@ jobs:
         with:
           toolchain: ${{ matrix.rust }}
           targets: ${{ matrix.target }}
-      # rust-toolchain.toml pins 1.95.0 — install the cross-compile target
+      # rust-toolchain.toml pins 1.97.1 — install the cross-compile target
       # for that toolchain too, since dtolnay/rust-toolchain only installs
       # for the matrix value which may differ from the pinned version.
       - run: rustup target add ${{ matrix.target }}
@@ -126,7 +126,7 @@ jobs:
       - uses: dtolnay/rust-toolchain@stable
         with:
           targets: wasm32-unknown-unknown
-      # rust-toolchain.toml pins 1.95.0 — install the wasm target for the pinned
+      # rust-toolchain.toml pins 1.97.1 — install the wasm target for the pinned
       # toolchain too (dtolnay installs for `stable`, which may differ).
       - run: rustup target add wasm32-unknown-unknown
       - uses: actions/setup-node@v4
@@ -155,7 +155,7 @@ jobs:
       - uses: dtolnay/rust-toolchain@stable
         with:
           targets: aarch64-unknown-linux-gnu
-      # rust-toolchain.toml pins 1.95.0 — install the aarch64 target for the
+      # rust-toolchain.toml pins 1.97.1 — install the aarch64 target for the
       # pinned toolchain too (dtolnay installs for `stable`, which may differ).
       - run: rustup target add aarch64-unknown-linux-gnu
       - name: install aarch64 cross toolchain + qemu-user
@@ -210,7 +210,7 @@ jobs:
     name: hpc-stream-parallel/rayon
     steps:
       - uses: actions/checkout@v4
-      - uses: dtolnay/rust-toolchain@1.95.0
+      - uses: dtolnay/rust-toolchain@1.97.1
       - uses: Swatinem/rust-cache@v2
       - uses: taiki-e/install-action@nextest
       - name: cargo check (no rayon — scalar path unchanged)
diff --git a/Cargo.toml b/Cargo.toml
index 1ab8a142..ef1bdcb5 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -3,7 +3,14 @@
 name = "ndarray"
 version = "0.17.2"
 edition = "2021"
-rust-version = "1.95"
+# Matches `rust-toolchain.toml` (1.97.1) and CI's `MSRV` / `BLAS_MSRV` env, which
+# are ALREADY 1.97.1. This said 1.95 until 2026-08-05 — a declared MSRV that
+# nothing tested, because no CI job builds at 1.95. Consumers read this field:
+# tesseract-rs path-deps both ndarray and lance-graph-contract, and a 1.95 build
+# of the contract crate happens to still succeed today — a coincidence, not a
+# guarantee, and exactly what an untested MSRV declaration buys. Declare what is
+# actually verified.
+rust-version = "1.97"
 authors = [
   "Ulrik Sverdrup \"bluss\"",
   "Jim Turner"
diff --git a/Dockerfile b/Dockerfile
index 32451500..a68d33c8 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,6 +1,6 @@
 # ndarray — Railway compile-test image (AVX2 default)
 # Verifies the HPC module builds cleanly (default + jit-native features)
-# Requires Rust 1.95.0 (LazyLock, simd_caps, modern std APIs)
+# Requires Rust 1.97.1 (LazyLock, simd_caps, modern std APIs)
 #
 # CPU detection & SIMD dispatch documentation: see Dockerfile.md
 # AVX-512 pinned variant: see Dockerfile.avx512
@@ -15,8 +15,8 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
     curl ca-certificates gcc libc6-dev pkg-config libssl-dev \
     && rm -rf /var/lib/apt/lists/*
 
-# Install Rust 1.95.0 via rustup — MUST match rust-toolchain.toml (channel =
-# "1.95.0") and Cargo.toml's `rust-version = "1.95"`. rust-toolchain.toml is
+# Install Rust 1.97.1 via rustup — MUST match rust-toolchain.toml (channel =
+# "1.97.1") and Cargo.toml's `rust-version = "1.97"`. rust-toolchain.toml is
 # deliberately NOT copied into the image (rustup would try to download a second
 # toolchain at build time), so this pin is the only thing keeping the image in
 # step with the repo — bump it whenever rust-toolchain.toml moves.
@@ -24,8 +24,8 @@ ENV RUSTUP_HOME=/usr/local/rustup \
     CARGO_HOME=/usr/local/cargo \
     PATH=/usr/local/cargo/bin:$PATH
 RUN curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | \
-    sh -s -- -y --default-toolchain 1.95.0 --profile minimal \
-    && rustc --version | grep -q "1.95.0"
+    sh -s -- -y --default-toolchain 1.97.1 --profile minimal \
+    && rustc --version | grep -q "1.97.1"
 
 WORKDIR /app
 
@@ -76,4 +76,4 @@ RUN cargo test --release --lib -- hpc:: 2>&1 && echo "=== HPC TESTS OK ==="
 # Minimal runtime image — just proves it compiled
 FROM debian:bookworm-slim
 COPY --from=builder /app/target/release/libndarray.rlib /usr/local/lib/
-CMD ["echo", "ndarray build verified — Rust 1.95.0"]
+CMD ["echo", "ndarray build verified — Rust 1.97.1"]
diff --git a/Dockerfile.avx512 b/Dockerfile.avx512
index 33a779ff..72fcbb0b 100644
--- a/Dockerfile.avx512
+++ b/Dockerfile.avx512
@@ -21,8 +21,8 @@ ENV RUSTUP_HOME=/usr/local/rustup \
     CARGO_HOME=/usr/local/cargo \
     PATH=/usr/local/cargo/bin:$PATH
 RUN curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | \
-    sh -s -- -y --default-toolchain 1.95.0 --profile minimal \
-    && rustc --version | grep -q "1.95.0"
+    sh -s -- -y --default-toolchain 1.97.1 --profile minimal \
+    && rustc --version | grep -q "1.97.1"
 
 WORKDIR /app
 
@@ -57,4 +57,4 @@ RUN cargo test --release --lib -- hpc:: 2>&1 && echo "=== AVX-512 HPC TESTS OK =
 
 FROM debian:bookworm-slim
 COPY --from=builder /app/target/release/libndarray.rlib /usr/local/lib/
-CMD ["echo", "ndarray AVX-512 build verified — Rust 1.95.0, target-cpu=x86-64-v4"]
+CMD ["echo", "ndarray AVX-512 build verified — Rust 1.97.1, target-cpu=x86-64-v4"]
diff --git a/rust-toolchain.toml b/rust-toolchain.toml
index e7ebd394..e912b989 100644
--- a/rust-toolchain.toml
+++ b/rust-toolchain.toml
@@ -1,10 +1,19 @@
 [toolchain]
-channel = "1.95.0"
-# Pinned to 1.95.0 (2026-04-14). Aligns ndarray with the rest of the
-# AdaWorldAPI stack: bevy (already on 1.95 for edition 2024) and
-# lance-graph (bumped in parallel). 1.95 introduced one new clippy lint
-# that fires on this codebase (`clippy::manual_checked_ops` on
-# `impl_owned_array.rs::into_scalar`); that's fixed in this same commit.
+channel = "1.97.1"
+# Pinned to 1.97.1 (2026-08-05). Aligns ndarray with the rest of the
+# AdaWorldAPI stack — lance-graph, OGAR, ruff, MedCare-rs, woa-rs, a2ui-rs and
+# stockfish-rs are all on 1.97.1; ndarray was the last sibling still declaring
+# 1.95, so a consumer path-dep'ing both it and lance-graph-contract saw two
+# different MSRVs.
+#
+# The channel here and `Cargo.toml`'s `rust-version` must move TOGETHER. They
+# were out of step between the 1.95 → 1.97.1 channel bump and 2026-08-05: this
+# file said 1.97.1 while the manifest still declared 1.95, and the comment below
+# still described the 1.95 rationale. A stale comment on a version pin is how the
+# next reader learns the wrong number.
+#
+# (Historical: the 1.95 bump introduced `clippy::manual_checked_ops`, which fired
+# on `impl_owned_array.rs::into_scalar` and was fixed in that same commit.)
 # Never auto-track `stable` — bump explicitly when a future version is
 # reviewed and the workspace clippy passes clean.
 components = ["clippy", "rustfmt"]
diff --git a/src/bitwise.rs b/src/bitwise.rs
index 0d849dde..59639269 100644
--- a/src/bitwise.rs
+++ b/src/bitwise.rs
@@ -634,7 +634,8 @@ mod tests {
     #[test]
     fn test_popcount_batch_u64() {
         let words = [0xFFFFFFFFFFFFFFFFu64, 0, 0x0F0F0F0F0F0F0F0F];
-        assert_eq!(super::popcount_batch_u64(&words), 64 + 0 + 32);
+        // per-word contributions: 64 + 0 + 32
+        assert_eq!(super::popcount_batch_u64(&words), 96);
     }
 
     #[test]
diff --git a/src/indexes.rs b/src/indexes.rs
index 762815e0..b432b9c4 100644
--- a/src/indexes.rs
+++ b/src/indexes.rs
@@ -57,10 +57,7 @@ where
     type Item = D::Pattern;
     #[inline]
     fn next(&mut self) -> Option<Self::Item> {
-        let index = match self.index {
-            None => return None,
-            Some(ref ix) => ix.clone(),
-        };
+        let index = self.index.clone()?;
         self.index = self.dim.next_for(index.clone());
         Some(index.into_pattern())
     }
diff --git a/src/iterators/mod.rs b/src/iterators/mod.rs
index e35bacc3..1a731087 100644
--- a/src/iterators/mod.rs
+++ b/src/iterators/mod.rs
@@ -488,10 +488,7 @@ impl<'a, A, D: Dimension> Iterator for IndexedIter<'a, A, D> {
     type Item = (D::Pattern, &'a A);
     #[inline]
     fn next(&mut self) -> Option<Self::Item> {
-        let index = match self.0.inner.index {
-            None => return None,
-            Some(ref ix) => ix.clone(),
-        };
+        let index = self.0.inner.index.clone()?;
         match self.0.next() {
             None => None,
             Some(elem) => Some((index.into_pattern(), elem)),
@@ -664,10 +661,7 @@ impl<'a, A, D: Dimension> Iterator for IndexedIterMut<'a, A, D> {
     type Item = (D::Pattern, &'a mut A);
     #[inline]
     fn next(&mut self) -> Option<Self::Item> {
-        let index = match self.0.inner.index {
-            None => return None,
-            Some(ref ix) => ix.clone(),
-        };
+        let index = self.0.inner.index.clone()?;
         match self.0.next() {
             None => None,
             Some(elem) => Some((index.into_pattern(), elem)),
diff --git a/src/palette_codec.rs b/src/palette_codec.rs
index 33683b4e..b1e39d85 100644
--- a/src/palette_codec.rs
+++ b/src/palette_codec.rs
@@ -807,8 +807,8 @@ mod tests {
 
         // Create states with a small palette
         let mut states = vec![0u16; 4096];
-        for i in 0..4096 {
-            states[i] = (i % 4) as u16;
+        for (i, state) in states.iter_mut().enumerate() {
+            *state = (i % 4) as u16;
         }
 
         let mut palette = HashMap::new();
diff --git a/src/property_mask.rs b/src/property_mask.rs
index 063b709e..0d02c76f 100644
--- a/src/property_mask.rs
+++ b/src/property_mask.rs
@@ -423,7 +423,7 @@ mod tests {
         assert!(m.test(0b1000)); // field = 10 => 2
         assert!(!m.test(0b0100)); // field = 01 => 1
         assert!(!m.test(0b1100)); // field = 11 => 3
-        assert!(m.test(0b11111_1000)); // field still 10
+        assert!(m.test(0b1_1111_1000)); // field still 10
     }
 
     #[test]