fix(deploy-win): don't re-patch an already-patched ISO

deploy-win patched its input into vm_dir/install-noprompt.iso and only its
own sidecar cache could skip the repack — so feeding an already-patched ISO
(e.g. from `template patch-win-iso`, or via --win-iso) triggered a wasteful
second extract+repack that double-injected the answer files.

deploy-win now detects a patched input (autounattend.xml present at the ISO
root via `iso_patch.iso_has_root_file`) and uses it as-is, skipping Step 4.
Raw ISOs are still patched once and cached as before.

src/ci_orchestrator/commands/template.py

@@ -2256,24 +2256,29 @@ def template_deploy_win(
     # ── Step 4: patch ISO (inject answer files + no-prompt boot) ───────────────
     _deploy_step("Step 4: patch ISO (inject autounattend + no-prompt boot)", 4, start_from_step)
     if start_from_step <= 4:
-        key = _patched_iso_inputs_key(base_iso, autounattend_xml, post_install_ps1)
-        sidecar = patched_iso.with_suffix(patched_iso.suffix + ".inputs")
-        cached = (
-            patched_iso.is_file()
-            and sidecar.is_file()
-            and sidecar.read_text(encoding="utf-8").strip() == key
-        )
-        if cached:
-            click.echo(f"  [OK] patched ISO up to date — skipping repack: {patched_iso}")
+        if win_iso_patch.iso_has_root_file(base_iso, "autounattend.xml"):
+            # Already patched (e.g. produced by `template patch-win-iso`) — use as-is.
+            click.echo(f"  [OK] ISO already patched (autounattend.xml present) — using as-is: {base_iso}")
+            patched_iso = base_iso
         else:
-            win_iso_patch.patch_iso(
-                base_iso,
-                autounattend_xml=autounattend_xml,
-                post_install_ps1=post_install_ps1,
-                out_iso=patched_iso,
-                work_dir=vm_dir,
+            key = _patched_iso_inputs_key(base_iso, autounattend_xml, post_install_ps1)
+            sidecar = patched_iso.with_suffix(patched_iso.suffix + ".inputs")
+            cached = (
+                patched_iso.is_file()
+                and sidecar.is_file()
+                and sidecar.read_text(encoding="utf-8").strip() == key
             )
-            sidecar.write_text(key, encoding="utf-8")
+            if cached:
+                click.echo(f"  [OK] patched ISO up to date — skipping repack: {patched_iso}")
+            else:
+                win_iso_patch.patch_iso(
+                    base_iso,
+                    autounattend_xml=autounattend_xml,
+                    post_install_ps1=post_install_ps1,
+                    out_iso=patched_iso,
+                    work_dir=vm_dir,
+                )
+                sidecar.write_text(key, encoding="utf-8")
 
     # ── Step 5: create VMDK ────────────────────────────────────────────────────
     _deploy_step("Step 5: create VMDK", 5, start_from_step)

src/ci_orchestrator/winimage/iso_patch.py

@@ -38,6 +38,18 @@ def _require_7z() -> str:
     raise click.ClickException("7z not found. Install p7zip-full.")
 
 
+def iso_has_root_file(iso: Path, name: str) -> bool:
+    """True if ``name`` exists at the root of ``iso`` (used to detect a patched ISO)."""
+    sevenz = _require_7z()
+    proc = subprocess.run(
+        [sevenz, "l", str(iso), f"-i!{name}"],
+        capture_output=True,
+        text=True,
+        check=False,
+    )
+    return proc.returncode == 0 and name.lower() in proc.stdout.lower()
+
+
 def _read_volid(base_iso: Path) -> str:
     """Read the ISO volume id (label); fall back to a sane default."""
     label = ""

tests/python/test_commands_deploy_win.py

@@ -194,6 +194,30 @@ def test_deploy_win_skips_patch_when_cached(
     assert "skipping repack" in result.output
 
 
+def test_deploy_win_uses_already_patched_iso(
+    tmp_path: Path, monkeypatch: pytest.MonkeyPatch
+) -> None:
+    root = tmp_path
+    (root / "iso").mkdir(parents=True)
+    (root / "iso" / "VMware-tools-windows.iso").write_bytes(b"tools")
+    base = root / "iso" / "ws.patched.iso"
+    base.write_bytes(b"win")
+    _patch_deploy(monkeypatch, root)
+    # Pretend the input ISO already carries autounattend.xml at its root.
+    monkeypatch.setattr(tmpl_mod.win_iso_patch, "iso_has_root_file", lambda *_a: True)
+
+    def boom(*_a: Any, **_k: Any) -> Path:
+        raise AssertionError("patch_iso must not run for an already-patched ISO")
+
+    monkeypatch.setattr(tmpl_mod.win_iso_patch, "patch_iso", boom)
+
+    result = CliRunner().invoke(
+        cli, ["template", "deploy-win", "--win-iso", str(base), "--nogui"]
+    )
+    assert result.exit_code == 0, result.output
+    assert "already patched" in result.output  # and boom (patch_iso) was never raised
+
+
 def test_deploy_win_iso_url_downloads(tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> None:
     root = tmp_path
     (root / "iso").mkdir(parents=True)

tests/python/test_winimage.py

@@ -127,6 +127,20 @@ def test_patch_iso_happy(monkeypatch: pytest.MonkeyPatch, tmp_path: Path) -> Non
     assert result == out and out.is_file()
 
 
+def test_iso_has_root_file(monkeypatch: pytest.MonkeyPatch, tmp_path: Path) -> None:
+    monkeypatch.setattr(ip, "_require_7z", lambda: "7z")
+    iso = tmp_path / "x.iso"
+    iso.write_bytes(b"x")
+
+    def fake_run(argv: list[str], **_k: Any) -> subprocess.CompletedProcess[str]:
+        out = "2026 .... 6813 autounattend.xml\n" if "-i!autounattend.xml" in argv else ""
+        return subprocess.CompletedProcess(argv, 0, out, "")
+
+    monkeypatch.setattr(ip.subprocess, "run", fake_run)
+    assert ip.iso_has_root_file(iso, "autounattend.xml") is True
+    assert ip.iso_has_root_file(iso, "missing.xml") is False
+
+
 def test_patch_iso_missing_efi_boot(monkeypatch: pytest.MonkeyPatch, tmp_path: Path) -> None:
     base = tmp_path / "base.iso"
     base.write_bytes(b"x" * 1000)