fix(simd): Phase 2 — preserve lowercase aliases under nightly-simd + rustfmt

Codex P1 on PR #173: the nightly-simd dispatch arm shadowed every other
re-export branch but dropped the lowercase aliases (`f32x16`, `f64x8`,
`u8x64`, etc.) that downstream code and docs reach for. Switching on
`--features nightly-simd` was therefore an API break instead of a
backend swap.

`src/simd_nightly/mod.rs`
  + 17 lowercase aliases (`f32x16` = `F32x16` etc.) matching the
    convention already present in `simd_avx2.rs`, `simd_avx512.rs`, and
    `src/simd_scalar.rs`. Reaches every numeric type the other backends
    expose under their lowercase names.

`src/simd.rs`
  + Lowercase names added to the nightly dispatch arm's `pub use`
    list so they reach `crate::simd::*` alongside the PascalCase ones.

  Also runs rustfmt against the file — the multi-clause `#[cfg(all(...))]`
  attrs that Phase 2 introduced exceed the column budget and rustfmt
  prefers the vertical block layout.

Author: claude

src/simd.rs

@@ -220,8 +220,9 @@ pub const PREFERRED_I16_LANES: usize = 16;
 // as soon as `nightly-simd` is on.
 #[cfg(feature = "nightly-simd")]
 pub use crate::simd_nightly::{
-    BF16x16, BF16x8, F16x16, F32Mask16, F32Mask8, F32x16, F32x8, F64Mask4, F64Mask8, F64x4, F64x8, I16x16, I16x32,
-    I32x16, I64x8, I8x32, I8x64, U16x32, U32x16, U32x8, U64x4, U64x8, U8x32, U8x64,
+    f32x16, f32x8, f64x4, f64x8, i16x16, i16x32, i32x16, i64x8, i8x32, i8x64, u16x32, u32x16, u32x8, u64x4, u64x8,
+    u8x32, u8x64, BF16x16, BF16x8, F16x16, F32Mask16, F32Mask8, F32x16, F32x8, F64Mask4, F64Mask8, F64x4, F64x8,
+    I16x16, I16x32, I32x16, I64x8, I8x32, I8x64, U16x32, U32x16, U32x8, U64x4, U64x8, U8x32, U8x64,
 };
 
 #[cfg(all(target_arch = "x86_64", target_feature = "avx512f", not(feature = "nightly-simd")))]
@@ -288,10 +289,18 @@ pub use crate::simd_avx512::{BF16x16, BF16x8};
 // `RUSTFLAGS="-D warnings"` env, which overrides our v3 config.toml,
 // landing on x86-64 baseline → the previous tighter `avx2` predicate
 // left no matching arm).
-#[cfg(all(target_arch = "x86_64", not(target_feature = "avx512f"), not(feature = "nightly-simd")))]
+#[cfg(all(
+    target_arch = "x86_64",
+    not(target_feature = "avx512f"),
+    not(feature = "nightly-simd")
+))]
 pub use crate::simd_avx512::{f32x8, f64x4, i16x16, i8x32, F32x8, F64x4, I16x16, I8x32};
 
-#[cfg(all(target_arch = "x86_64", not(target_feature = "avx512f"), not(feature = "nightly-simd")))]
+#[cfg(all(
+    target_arch = "x86_64",
+    not(target_feature = "avx512f"),
+    not(feature = "nightly-simd")
+))]
 pub use crate::simd_avx2::{
     f32x16, f64x8, i16x32, i32x16, i64x8, i8x64, u32x16, u64x8, u8x64, F32Mask16, F32x16, F64Mask8, F64x8, I16x32,
     I32x16, I64x8, I8x64, U16x32, U32x16, U64x8, U8x64,
@@ -1593,7 +1602,11 @@ pub use scalar::{
 };
 
 // Other non-x86 targets (wasm, riscv, etc.): full scalar fallback.
-#[cfg(all(not(target_arch = "x86_64"), not(target_arch = "aarch64"), not(feature = "nightly-simd")))]
+#[cfg(all(
+    not(target_arch = "x86_64"),
+    not(target_arch = "aarch64"),
+    not(feature = "nightly-simd")
+))]
 pub use scalar::{
     f32x16, f32x8, f64x4, f64x8, i16x16, i16x32, i32x16, i64x8, i8x32, i8x64, u32x16, u64x8, u8x64, F32Mask16, F32x16,
     F32x8, F64Mask8, F64x4, F64x8, I16x16, I16x32, I32x16, I64x8, I8x32, I8x64, U16x32, U32x16, U64x8, U8x64,

src/simd_nightly/mod.rs

@@ -43,3 +43,43 @@ pub use i_word_types::{I16x16, I16x32, I32x16, I64x8};
 pub use masks::{F32Mask16, F32Mask8, F64Mask4, F64Mask8};
 pub use u8_types::{U8x32, U8x64};
 pub use u_word_types::{U16x32, U32x16, U32x8, U64x4, U64x8};
+
+// Lowercase aliases — match the std::simd convention used by
+// `simd_avx2.rs`, `simd_avx512.rs`, and the scalar fallback in
+// `simd_scalar.rs`. Consumer docs and downstream code import names like
+// `crate::simd::f32x16`; without these aliases, enabling `nightly-simd`
+// would silently break those imports (codex P1 on PR #173).
+#[allow(non_camel_case_types)]
+pub type f32x16 = F32x16;
+#[allow(non_camel_case_types)]
+pub type f32x8 = F32x8;
+#[allow(non_camel_case_types)]
+pub type f64x8 = F64x8;
+#[allow(non_camel_case_types)]
+pub type f64x4 = F64x4;
+#[allow(non_camel_case_types)]
+pub type u8x64 = U8x64;
+#[allow(non_camel_case_types)]
+pub type u8x32 = U8x32;
+#[allow(non_camel_case_types)]
+pub type u16x32 = U16x32;
+#[allow(non_camel_case_types)]
+pub type u32x16 = U32x16;
+#[allow(non_camel_case_types)]
+pub type u32x8 = U32x8;
+#[allow(non_camel_case_types)]
+pub type u64x8 = U64x8;
+#[allow(non_camel_case_types)]
+pub type u64x4 = U64x4;
+#[allow(non_camel_case_types)]
+pub type i8x64 = I8x64;
+#[allow(non_camel_case_types)]
+pub type i8x32 = I8x32;
+#[allow(non_camel_case_types)]
+pub type i16x32 = I16x32;
+#[allow(non_camel_case_types)]
+pub type i16x16 = I16x16;
+#[allow(non_camel_case_types)]
+pub type i32x16 = I32x16;
+#[allow(non_camel_case_types)]
+pub type i64x8 = I64x8;