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: "27 3 * * *"
   push:
-    branches: [main]
+    branches: [release]
   pull_request:
     paths:
-      - Cargo.toml
-      - Cargo.lock
-      - "**/Cargo.toml"
       - .github/workflows/freebsd.yml
       - packaging/freebsd/**
+      - packaging/env.sh
   workflow_dispatch:
 
 concurrency:

.github/workflows/windows-arm64.yml

@@ -3,19 +3,17 @@
 # run the test suite natively on ARM64.
 name: Windows ARM64
 
+# Nightly on main and on pushes to `release` (dependency and runner-image drift shows up within a
+# day, and always before a release ships), and on PRs that change the Windows packaging itself.
 on:
+  schedule:
+    - cron: "43 5 * * *"
   push:
-    branches: [main]
+    branches: [release]
   pull_request:
     paths:
-      - Cargo.toml
-      - Cargo.lock
-      - "**/Cargo.toml"
-      - "**/build.rs"
       - .github/workflows/windows-arm64.yml
       - packaging/windows/**
-  schedule:
-    - cron: "41 4 * * 1" # weekly, so drift in the runner images shows up
   workflow_dispatch:
 
 concurrency: