craft-audio: review fixes, round 18 (#442)

CI: time-limit and retry the ffmpeg install. A stalled apt mirror used
up the oracle job's 20 minutes on #442, #443 and #447 before any test
ran, and its log is only printed when the step fails. Each try now gets
3 minutes, up to three tries, and a timed-out install prints why.

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

.github/workflows/audio.yml

@@ -102,7 +102,16 @@ jobs:
         run: |
           # The man-db index rebuild after dpkg is slow on hosted runners.
           sudo rm -f /var/lib/man-db/auto-update
-          (sudo apt-get update -qq && sudo apt-get install -y -qq --no-install-recommends ffmpeg) > "$RUNNER_TEMP/apt.log" 2>&1 &
+          # A mirror can stall for most of the job's time limit, and the next try usually gets a good one.
+          install_ffmpeg() {
+            for attempt in 1 2 3; do
+              timeout -k 10 180 sudo sh -c 'apt-get update -qq && apt-get install -y -qq --no-install-recommends ffmpeg' && return 0
+              echo "apt: attempt $attempt failed with exit code $?"
+              sudo dpkg --configure -a || true
+            done
+            return 1
+          }
+          install_ffmpeg > "$RUNNER_TEMP/apt.log" 2>&1 &
           apt=$!
           cargo test -p craft-audio --all-features --locked --no-run
           wait "$apt" || { cat "$RUNNER_TEMP/apt.log"; exit 1; }