fix(ci): set keychain timeout to 30min to prevent notarization failure

The macOS CI runner's keychain auto-locks after 5 minutes (system
default), but Apple notarization takes 5-10 minutes. By the time
notarization completes, the keychain is locked and the log fetch +
staple step fails with keychainLocked error.

Set keychain timeout to 1800s (30 min) with -u (lock on sleep only).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: dvschultz

.github/workflows/build-macos.yml

@@ -406,6 +406,7 @@ jobs:
           security create-keychain -p "$KEYCHAIN_PASSWORD" build.keychain
           security default-keychain -s build.keychain
           security unlock-keychain -p "$KEYCHAIN_PASSWORD" build.keychain
+          security set-keychain-settings -t 1800 -u build.keychain
           security import certificate.p12 \
             -k build.keychain \
             -P "$MACOS_CERTIFICATE_PWD" \