fix(release): give rustc 1.99 enough stack; Windows build fails fast

rustc 1.99 overflows its default 8 MB stack compiling the crate in
release on Windows and macOS. Raise RUST_MIN_STACK to 64 MB in the cargo
config and the release workflow (the latter also covers rebuilding older
commits). The Windows Build step now runs in bash so a failed cargo build
stops the job instead of surfacing later as a missing exe at signing.
workflow_dispatch gains tag/commit inputs to rebuild a published release.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

.cargo/config.toml

@@ -30,6 +30,8 @@ rustflags = [
     "-Clink-arg=/STACK:16777216",
 ]
 
+# Also sizes rustc's own threads: rustc 1.99 overflows the default 8 MB
+# compiling this crate in release on Windows/macOS.
 [env]
-RUST_MIN_STACK = "8388608"
+RUST_MIN_STACK = "67108864"