ci: move ndarray's hardcoded toolchain pins to 1.98.1 too

Caught by reading the PR's own check names: CI reported tests/1.97.1 and
clippy/1.97.1 AFTER the toolchain file said 1.98.1. Unlike lance-graph, whose
eleven workflows all read rust-toolchain.toml with no toolchain input, this
repo's CI pins the version explicitly via dtolnay/rust-toolchain@<version> plus
an MSRV env var. So bumping rust-toolchain.toml alone left CI still testing the
OLD toolchain — the bump would have been cosmetic where it is actually gated.

Six real pins moved: MSRV, BLAS_MSRV, the clippy matrix entry, and three
dtolnay/rust-toolchain@ steps.

Six comments also restated the version in prose and are rewritten rather than
edited, the same lesson rust-toolchain.toml already carries: a stale comment on
a version pin is how the next reader learns the wrong number. The matrix
comment now names WHERE the number lives (three places in this file, because CI
does not read the toolchain file) instead of duplicating the number itself, and
points at the bump log as the single record of why each move happened. The
comment it replaces still described the 1.94.1 bump as 'this PR'.

Verified: zero remaining 1.97.1 references in ci.yaml, and the YAML parses.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AGVLyRZNEKKBSfBDJfbY3V

Author: claude

.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: 1.97.1
-  BLAS_MSRV: 1.97.1
+  MSRV: 1.98.1
+  BLAS_MSRV: 1.98.1
 
 jobs:
   pass-msrv:
@@ -41,18 +41,19 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        # 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.
+        # Must equal `rust-toolchain.toml`'s channel. The version is NOT
+        # restated in this comment on purpose: CI here does NOT read the
+        # toolchain file (it uses `dtolnay/rust-toolchain@<version>`), so the
+        # number lives in three places — the `MSRV`/`BLAS_MSRV` env above, the
+        # matrix entry below, and each `dtolnay/rust-toolchain@` step. All of
+        # them move together with the toolchain file, and its bump log is the
+        # one place that records WHY each move happened.
         rust:
-          - "1.97.1"
+          - "1.98.1"
     name: clippy/${{ matrix.rust }}
     steps:
       - uses: actions/checkout@v4
-      - uses: dtolnay/rust-toolchain@1.97.1
+      - uses: dtolnay/rust-toolchain@1.98.1
         with:
           components: clippy
       - uses: Swatinem/rust-cache@v2
@@ -74,10 +75,10 @@ jobs:
     # That state no longer exists; the band-aid is removed in this PR.
     steps:
       - uses: actions/checkout@v4
-      # 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@1.97.1
+      # Stable rustfmt on the pinned channel (see `rust-toolchain.toml`;
+      # version deliberately not restated here). No nightly dependency since
+      # rustfmt.toml is stable-clean post-PR #133.
+      - uses: dtolnay/rust-toolchain@1.98.1
         with:
           components: rustfmt
       - run: cargo fmt --all --check
@@ -99,7 +100,7 @@ jobs:
         with:
           toolchain: ${{ matrix.rust }}
           targets: ${{ matrix.target }}
-      # rust-toolchain.toml pins 1.97.1 — install the cross-compile target
+      # rust-toolchain.toml pins the channel — 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 +127,7 @@ jobs:
       - uses: dtolnay/rust-toolchain@stable
         with:
           targets: wasm32-unknown-unknown
-      # rust-toolchain.toml pins 1.97.1 — install the wasm target for the pinned
+      # rust-toolchain.toml pins the channel — 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 +156,7 @@ jobs:
       - uses: dtolnay/rust-toolchain@stable
         with:
           targets: aarch64-unknown-linux-gnu
-      # rust-toolchain.toml pins 1.97.1 — install the aarch64 target for the
+      # rust-toolchain.toml pins the channel — 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 +211,7 @@ jobs:
     name: hpc-stream-parallel/rayon
     steps:
       - uses: actions/checkout@v4
-      - uses: dtolnay/rust-toolchain@1.97.1
+      - uses: dtolnay/rust-toolchain@1.98.1
       - uses: Swatinem/rust-cache@v2
       - uses: taiki-e/install-action@nextest
       - name: cargo check (no rayon — scalar path unchanged)