refactor: flatten test harness storage compat aliases (#3596)

* refactor: flatten test harness storage compat aliases

* refactor: flatten rustfs storage compat aliases (#3597)

* refactor: prune runtime storage compat surface (#3598)

* refactor: flatten runtime secondary storage compat (#3599)

* docs: add scheduler placement profiling baselines (#3600)

* feat: add observability topology capability contracts (#3601)

scripts/check_architecture_migration_rules.sh

@@ -65,6 +65,10 @@ STORE_API_EXTERNAL_LIST_CONSUMER_HITS_FILE="${TMP_DIR}/store_api_external_list_c
 STORE_API_EXTERNAL_OPERATION_CONSUMER_HITS_FILE="${TMP_DIR}/store_api_external_operation_consumer_hits.txt"
 STORE_API_OBJECT_OPERATION_LOCAL_METHOD_HITS_FILE="${TMP_DIR}/store_api_object_operation_local_method_hits.txt"
 DIRECT_ECSTORE_IMPORT_HITS_FILE="${TMP_DIR}/direct_ecstore_import_hits.txt"
+TEST_HARNESS_NESTED_STORAGE_COMPAT_HITS_FILE="${TMP_DIR}/test_harness_nested_storage_compat_hits.txt"
+RUSTFS_NESTED_STORAGE_COMPAT_HITS_FILE="${TMP_DIR}/rustfs_nested_storage_compat_hits.txt"
+RUSTFS_RUNTIME_SCALAR_STORAGE_COMPAT_HITS_FILE="${TMP_DIR}/rustfs_runtime_scalar_storage_compat_hits.txt"
+RUSTFS_RUNTIME_SECONDARY_STORAGE_COMPAT_HITS_FILE="${TMP_DIR}/rustfs_runtime_secondary_storage_compat_hits.txt"
 PRODUCTION_UNUSED_COMPAT_ALLOW_HITS_FILE="${TMP_DIR}/production_unused_compat_allow_hits.txt"
 BROAD_STORE_API_COMPAT_REEXPORT_HITS_FILE="${TMP_DIR}/broad_store_api_compat_reexport_hits.txt"
 NESTED_STORE_API_COMPAT_MODULE_HITS_FILE="${TMP_DIR}/nested_store_api_compat_module_hits.txt"
@@ -204,10 +208,18 @@ require_source_line \
   "crates/storage-api/src/lib.rs" \
   "pub use bucket::{BucketInfo, BucketOperations, BucketOptions, DeleteBucketOptions, MakeBucketOptions, SRBucketDeleteOp};" \
   "storage-api public bucket contract re-export"
+require_source_line \
+  "crates/storage-api/src/lib.rs" \
+  "pub use capability::{CapabilitySnapshotError, CapabilityState, CapabilityStatus};" \
+  "storage-api public capability contract re-export"
 require_source_line \
   "crates/storage-api/src/lib.rs" \
   "pub use multipart::{CompletePart, ListMultipartsInfo, ListPartsInfo, MultipartInfo, MultipartUploadResult, PartInfo};" \
   "storage-api public multipart DTO re-export"
+require_source_line \
+  "crates/storage-api/src/lib.rs" \
+  "pub use observability::{" \
+  "storage-api public observability contract re-export"
 require_source_line \
   "crates/storage-api/src/lib.rs" \
   "pub use object::{HTTPPreconditions, HTTPRangeError, HTTPRangeSpec, ObjectLockRetentionOptions};" \
@@ -240,6 +252,10 @@ require_source_line \
   "crates/storage-api/src/lib.rs" \
   "pub use error::{StorageErrorCode, StorageResult};" \
   "storage-api public error contract re-export"
+require_source_line \
+  "crates/storage-api/src/lib.rs" \
+  "pub use topology::{" \
+  "storage-api public topology contract re-export"
 
 (
   cd "$ROOT_DIR"
@@ -403,6 +419,66 @@ if [[ -s "$DIRECT_ECSTORE_IMPORT_HITS_FILE" ]]; then
   report_failure "direct rustfs_ecstore imports outside compatibility boundaries are forbidden: $(paste -sd '; ' "$DIRECT_ECSTORE_IMPORT_HITS_FILE")"
 fi
 
+(
+  cd "$ROOT_DIR"
+  rg -n --no-heading '\bstorage_compat::ecstore\b|\bmod\s+ecstore\b' \
+    crates/e2e_test/src crates/heal/tests crates/scanner/tests fuzz/fuzz_targets \
+    --glob '*.rs' \
+    --glob '!target/**' || true
+) >"$TEST_HARNESS_NESTED_STORAGE_COMPAT_HITS_FILE"
+
+if [[ -s "$TEST_HARNESS_NESTED_STORAGE_COMPAT_HITS_FILE" ]]; then
+  report_failure "test and fuzz storage compatibility harnesses must use direct aliases instead of nested ecstore modules: $(paste -sd '; ' "$TEST_HARNESS_NESTED_STORAGE_COMPAT_HITS_FILE")"
+fi
+
+(
+  cd "$ROOT_DIR"
+  rg -n --no-heading '\bstorage_compat::ecstore\b|\bmod\s+ecstore\b' \
+    rustfs/src \
+    --glob '*.rs' \
+    --glob '!target/**' || true
+) >"$RUSTFS_NESTED_STORAGE_COMPAT_HITS_FILE"
+
+if [[ -s "$RUSTFS_NESTED_STORAGE_COMPAT_HITS_FILE" ]]; then
+  report_failure "RustFS runtime storage compatibility paths must use direct aliases instead of nested ecstore modules: $(paste -sd '; ' "$RUSTFS_NESTED_STORAGE_COMPAT_HITS_FILE")"
+fi
+
+(
+  cd "$ROOT_DIR"
+  rg -n --no-heading '\bstorage_compat::(?:store|error|global|endpoints|set_disk|rpc|metrics_realtime|notification_sys|admin_server_info|store_utils|data_usage|disks_layout|event_notification)::|\bstorage_compat::disk::(?:RUSTFS_META_BUCKET|DiskAPI|endpoint::Endpoint)\b|\bstorage_compat::\{[^}\n]*(?:store|error|global|endpoints|set_disk|rpc|metrics_realtime|notification_sys|admin_server_info|store_utils|data_usage|disks_layout|event_notification|disk)::' \
+    rustfs/src \
+    --glob '*.rs' \
+    --glob '!target/**' || true
+) >"$RUSTFS_RUNTIME_SCALAR_STORAGE_COMPAT_HITS_FILE"
+
+if [[ -s "$RUSTFS_RUNTIME_SCALAR_STORAGE_COMPAT_HITS_FILE" ]]; then
+  report_failure "RustFS runtime scalar storage compatibility paths must use direct aliases instead of secondary modules: $(paste -sd '; ' "$RUSTFS_RUNTIME_SCALAR_STORAGE_COMPAT_HITS_FILE")"
+fi
+
+(
+  cd "$ROOT_DIR"
+  {
+    rg -n --no-heading '\bstorage_compat::(?:bucket|config|rio|client|tier|compress|disk|rebalance)::' \
+      rustfs/src \
+      --glob '*.rs' \
+      --glob '!target/**' || true
+    rg -n --no-heading '\bpub\(crate\)\s+mod\s+(?:bucket|config|rio|client|tier|compress|disk|rebalance)\b' \
+      rustfs/src \
+      --glob '*storage_compat.rs' \
+      --glob '!target/**' || true
+    find rustfs/src -type f -name '*.rs' -print0 |
+      xargs -0 perl -0ne '
+        while (/use\s+crate::(?:app::|admin::|storage::)?storage_compat::\{[^;]*?\b(bucket|config|rio|client|tier|compress|disk|rebalance)::/sg) {
+          print "$ARGV:grouped storage_compat::$1 import\n";
+        }
+      '
+  }
+) >"$RUSTFS_RUNTIME_SECONDARY_STORAGE_COMPAT_HITS_FILE"
+
+if [[ -s "$RUSTFS_RUNTIME_SECONDARY_STORAGE_COMPAT_HITS_FILE" ]]; then
+  report_failure "RustFS runtime secondary storage compatibility paths must use direct aliases instead of bucket/config/rio/client/tier/compress/disk/rebalance modules: $(paste -sd '; ' "$RUSTFS_RUNTIME_SECONDARY_STORAGE_COMPAT_HITS_FILE")"
+fi
+
 (
   cd "$ROOT_DIR"
   rg -n --no-heading '#!\[allow\(unused_imports\)\]' \