CI: run FreeBSD and Windows ARM64 checks nightly and on release, not per PR

They ran on every push to main and on any PR touching Cargo.toml/Cargo.lock,
which is nearly every PR. See craftrules release/playbook.md §2.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

.github/workflows/freebsd.yml

@@ -2,16 +2,19 @@
 # (GitHub has no FreeBSD runners). GPU tests skip themselves when the VM has no adapter.
 name: FreeBSD
 
+# The VM build is slow, so it runs nightly on main and on pushes to `release`, not on every push
+# or dependency change: a drifted dependency still shows up within a day, and always before a
+# release ships. PRs that change the FreeBSD packaging itself still run it.
 on:
+  schedule:
+    - cron: "7 2 * * *"
   push:
-    branches: [main]
+    branches: [release]
   pull_request:
     paths:
-      - Cargo.toml
-      - Cargo.lock
-      - "**/Cargo.toml"
       - "crates/fonts/**"
       - .github/workflows/freebsd.yml
+      - packaging/freebsd/**
   workflow_dispatch:
 
 concurrency: