test(scanner): supply explicit coverage in publication fixtures

Keep the confirmed-empty namespace fixture authoritative under the required
coverage contract and qualify the bucket cache metadata test type.

Co-Authored-By: heihutu <heihutu@gmail.com>
Co-Authored-By: zhi22915 <qiuzgang@gmail.com>

crates/scanner/src/scanner/tests.rs

@@ -8607,7 +8607,7 @@ fn scoped_scan_remote_dirty_coverage_invalidates_local_bucket_current() {
     );
     let source = DataUsageCacheSource::new(0, 0);
     let mut cache = DataUsageCache {
-        info: DataUsageCacheInfo {
+        info: crate::DataUsageCacheInfo {
             name: "bucket".to_string(),
             next_cycle: 7,
             leader_epoch: 11,

crates/scanner/src/scanner_io/publish_gate_tests.rs

@@ -859,6 +859,7 @@ fn completed_data_usage_info_publishes_confirmed_empty_namespace() {
             source: Some(DataUsageCacheSource::new(0, 0)),
             snapshot_complete: true,
             scan_plan_digest: Some(TEST_PLAN_DIGEST),
+            scan_coverage_digest: Some(TEST_COVERAGE_DIGEST),
             cache_key_format: DATA_USAGE_CACHE_KEY_FORMAT,
             ..Default::default()
         },