blaze-host: scope the dirty-tree check to the crates the binary is built from

A whole-repo check read DIRTY permanently, because unrelated submodules carry
pre-existing modifications. A warning that is always on is a warning nobody
reads, which defeats the point: the flag exists so a mutated build announces
itself before it can be mistaken for parity evidence.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

openfut-blaze-host/build.rs

@@ -23,9 +23,24 @@ fn git(args: &[&str]) -> Option<String> {
 fn main() {
     let commit = git(&["rev-parse", "--short=7", "HEAD"]).unwrap_or_else(|| "unknown".into());
 
-    // Tracked modifications only: untracked scratch files are not a build
-    // difference, but an edited source file certainly is.
-    let dirty = match git(&["status", "--porcelain", "--untracked-files=no"]) {
+    // Scoped to the crates this binary is actually built from.
+    //
+    // A whole-repo check reads DIRTY permanently here, because unrelated
+    // submodules carry pre-existing modifications. A warning that is always on
+    // is a warning nobody reads — which would defeat the point, since the whole
+    // job of this flag is to make a mutated build announce itself.
+    //
+    // Untracked files are excluded: scratch output is not a build difference,
+    // but an edited source file certainly is.
+    let dirty = match git(&[
+        "status",
+        "--porcelain",
+        "--untracked-files=no",
+        "--",
+        "openfut-blaze-host",
+        "openfut-adapter-fifa17",
+        "openfut-protocol-blaze",
+    ]) {
         Some(s) if !s.is_empty() => "DIRTY",
         Some(_) => "clean",
         None => "unknown",