chore(rust): sync nightly with vite-task (2026-03-05)

The reviewer asked us to share a single nightly with voidzero-dev/
vite-task, whose rust-toolchain.toml is currently pinned to
nightly-2026-03-05. Match that and replace the date-rationale comment
with a directive that future bumps track the vite-task pin.

The earlier rationale (oxc_transformer >=0.130 needs `if_let_guard`,
stabilized in rustc 1.94 / 2026-01-29) is still satisfied — any
nightly past late January 2026 works.

Author: fengmk2

rust-toolchain.toml

@@ -3,12 +3,7 @@
 # - cargo `Z-bindeps` to build and embed preload shared libraries as dependencies of fspy
 # - `windows_process_extensions_main_thread_handle` to get the main thread handle for Detours injection
 #
-# Why this date in particular:
-# - oxc_transformer (>=0.130) uses `if let` guards inside match arms (`if_let_guard`,
-#   rust-lang/rust#51114). That feature stabilized in rustc 1.94 (released 2026-01-29),
-#   so any nightly from late January 2026 onward compiles it. Earlier pins (e.g.
-#   nightly-2025-12-11) hit E0658 during `cargo clippy --all-features`.
-# Bump in lockstep with upstream oxc/rolldown updates; pick any nightly past the
-# stabilization date for the features the new versions use.
-channel = "nightly-2026-03-15"
+# Keep this pinned to the same date as voidzero-dev/vite-task's rust-toolchain.toml
+# so the two repos share a single nightly. Bumps should track that file.
+channel = "nightly-2026-03-05"
 profile = "default"