fix(fspy_test_bin): force static linking for seccomp test binary

The global -crt-static flag (for dynamic musl linking) would make
fspy_test_bin dynamically linked, but it must remain static so fspy can
test its seccomp-based tracing path for static executables. Pass
-static to the linker via build.rs to override the global flag.

https://claude.ai/code/session_01R3RoGqPDBRtNa2NRg3SeBM

Author: claude

crates/fspy_test_bin/build.rs

@@ -0,0 +1,7 @@
+fn main() {
+    // fspy_test_bin must be a statically-linked executable so fspy can test
+    // its seccomp-based tracing path (used for static binaries that make raw
+    // syscalls instead of going through a preloaded libc shim).
+    // Force +crt-static even when the global RUSTFLAGS contain -crt-static.
+    println!("cargo::rustc-link-arg=-static");
+}