ci: optimizations

Author: evansims

.github/workflows/ci.yml

@@ -7,6 +7,9 @@ on:
     branches: [main]
   pull_request:
     branches: [main]
+  schedule:
+    # Nightly at midnight UTC (for coverage)
+    - cron: "0 0 * * *"
 
 # Cancel in-progress runs when new commits are pushed
 concurrency:
@@ -239,12 +242,12 @@ jobs:
       - name: Test with blocking
         run: cargo nextest run --lib --features blocking
 
-  # Code coverage (non-blocking, for information only)
+  # Code coverage (nightly only to reduce CI costs)
   coverage:
     name: Code Coverage
     needs: test
     runs-on: ubuntu-latest
-    if: github.actor != 'dependabot[bot]'
+    if: github.event_name == 'schedule'
     continue-on-error: true
     env:
       RUSTFLAGS: "-C codegen-units=16 -C link-arg=-fuse-ld=mold"