Scope the qa matrix to the platforms each crate actually supports

The first cut ran release-profile tests on all three platforms everywhere,
which invented coverage no crate had ever claimed. bdemu is Linux-only — its
ci.yml has no macOS or Windows job at all, and its tests call
ExitStatus::signal(), which does not exist on Windows, so they do not compile
there let alone run. The rest follow the policy ci.yml already set: tests
execute on Linux and macOS, Windows compiles them so the cfg(windows) halves
still get codegen before release time.

That policy is now explicit in qa.yml as a windows-build job rather than
implied by which jobs happen to exist.

Recorded, not papered over: running the suites on Windows DOES find real
defects — autorip has five Windows path-handling failures in mover.rs and
freemkv-engine has three tests hardcoding /dev/null. freemkv ships a Windows
GUI, so they matter. They are pre-existing rather than 1.6.1 regressions, and
fixing them is its own piece of work.

Also build the binary before cli-parity.sh. cli-integration.sh builds its own;
cli-parity.sh only checks for one and exits 2 with "build it first", so both
legs died before running a single case.

.github/workflows/qa.yml

@@ -68,7 +68,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [ubuntu-latest, macos-latest, windows-latest]
+        os: ['ubuntu-latest', 'macos-latest']
     runs-on: ${{ matrix.os }}
     steps:
       - uses: actions/checkout@v5
@@ -109,3 +109,25 @@ jobs:
       - run: rustup target add x86_64-unknown-linux-gnu
       - run: cargo clippy --all-targets --target x86_64-unknown-linux-gnu -- -D warnings
         working-directory: libfreemkv
+
+  # Windows compiles the tests but does not run them, matching the policy
+  # ci.yml already set. The value here is codegen: the #[cfg(windows)] halves
+  # of the SCSI transport and platform layers compile on no other runner, so
+  # without this they are first built at release time.
+  windows-build:
+    runs-on: windows-latest
+    steps:
+      - uses: actions/checkout@v5
+        with:
+          path: libfreemkv
+      - uses: actions/checkout@v5
+        with:
+          repository: freemkv/freemkv-unlock
+          ref: qa
+          path: freemkv-unlock
+      - uses: dtolnay/rust-toolchain@1.97.0
+      - uses: Swatinem/rust-cache@v2
+        with:
+          workspaces: libfreemkv
+      - run: cargo build --release --tests
+        working-directory: libfreemkv