ci: require one cached Dylint preflight

.github/workflows/ci-preflight.yml

@@ -47,7 +47,7 @@ on:
         type: boolean
         default: true
       dylint:
-        description: Run the repository Dylint gate. Enabled only for the native Linux x86 lane.
+        description: Run both workspace Dylints on the single Linux x86 lane.
         type: boolean
         default: false
       cache-targets:
@@ -200,7 +200,7 @@ jobs:
           path: logs/kernel-substrate-timing.json
           if-no-files-found: warn
 
-      # Dylint is intentionally a single Linux-x86 step. Its nightly artifacts
+      # Dylint runs once on Linux x86. Its nightly artifacts
       # use a dedicated persistent cache so they cannot mix with the stable
       # workspace build or impose a cold rebuild on every platform lane.
       - name: Install Dylint nightly
@@ -265,6 +265,7 @@ jobs:
           CARGO_BIN: cargo
           CARGO_TARGET_DIR: ${{ runner.temp }}/running-process-dylint-target
         run: |
+          rustup run nightly-2026-04-16 "$CARGO_BIN" dylint --all --workspace
           rustup run nightly-2026-04-16 "$CARGO_BIN" dylint --path lints --pattern running-process-platform-boundary --workspace
 
       # #1216: save only on main; PR runs restore main's entry.

lints/running-process-platform-boundary/ui/main.rs

@@ -1,4 +1,4 @@
 fn main() {
-    #[cfg(any(windows, not(target_os = "linux")))]
+    #[cfg(all(windows, not(target_os = "linux")))]
     use std::os::windows::process::CommandExt as _;
 }

lints/running-process-platform-boundary/ui/main.stderr

@@ -9,13 +9,13 @@ LL |     use std::os::windows::process::CommandExt as _;
 error: host-platform cfg selection (windows) is not allowed here; host selection belongs in crates/running-process-platform-internal/src/lib.rs cfg_select!
   --> $DIR/main.rs:2:15
    |
-LL |     #[cfg(any(windows, not(target_os = "linux")))]
+LL |     #[cfg(all(windows, not(target_os = "linux")))]
    |               ^^^^^^^
 
 error: host-platform cfg selection (target_os) is not allowed here; host selection belongs in crates/running-process-platform-internal/src/lib.rs cfg_select!
   --> $DIR/main.rs:2:28
    |
-LL |     #[cfg(any(windows, not(target_os = "linux")))]
+LL |     #[cfg(all(windows, not(target_os = "linux")))]
    |                            ^^^^^^^^^^^^^^^^^^^
 
 error: aborting due to 3 previous errors

tests/test_ci_lint.py

@@ -3,6 +3,20 @@
 from ci import lint as ci_lint
 
 
+def test_one_linux_preflight_gates_both_workspace_dylints() -> None:
+    workflows = ci_lint.ROOT / ".github" / "workflows"
+    reusable = (workflows / "ci-preflight.yml").read_text(encoding="utf-8")
+    assert "dylint --all --workspace" in reusable
+    assert "--pattern running-process-platform-boundary" in reusable
+    for name in ("ci-linux.yml", "ci-macos.yml", "ci-windows.yml"):
+        source = (workflows / name).read_text(encoding="utf-8")
+        for label in ("linux-x86", "linux-arm") if name == "ci-linux.yml" else (
+            ("macos-x86", "macos-arm") if name == "ci-macos.yml" else ("windows-x86", "windows-arm")
+        ):
+            job = source.split(f"label: {label}", 1)[1].split("\n\n", 1)[0]
+            assert ("dylint: true" in job) == (label == "linux-x86"), (name, label)
+
+
 def test_main_runs_lint_commands_through_running_process_cli(monkeypatch) -> None:
     commands: list[list[str]] = []
     monkeypatch.setattr(