refactor(5 test files): selective imports + remove dangling (ADR-025 L2)

Five test files, 2 stars each -> selective.

config/encryption_tests.nu:
  config/encryption.nu [7 symbols]
  kms/client.nu        [kms-status]

extensions/tests/test_cache.nu:
  extensions/cache.nu  DROPPED (dead)
  utils/logger.nu      REMOVED (file does not exist — dangling)

extensions/tests/test_oci_client.nu:
  oci/client.nu   [4 symbols]
  utils/logger.nu REMOVED (dangling)

extensions/tests/test_discovery.nu:
  extensions/discovery.nu [5 symbols]
  utils/logger.nu         REMOVED (dangling)

config/loader/test.nu:
  config/validators.nu   [validate-interpolation]
  config/interpolators   DROPPED (dead)

Pre-existing bug found and removed: 3 test files imported
`../../utils/logger.nu` which doesn't exist. Star-import silenced the
missing-file error; with selective imports it would fail. Cleanest fix:
remove the dangling import (the files never actually used any symbols
from logger.nu — it was a zombie import from a long-deleted file).

Validation: 4 files 0 errors. encryption_tests.nu has 1 pre-existing
error matching baseline.

Refs: ADR-025

nulib/lib_provisioning/config/encryption_tests.nu

@@ -2,8 +2,12 @@
 # Comprehensive test suite for encryption functionality
 # Error handling: Guard patterns (no try-catch for field access)
 
-use encryption.nu *
-use ../kms/client.nu *
+# Selective imports (ADR-025 Phase 3 Layer 2).
+use lib_provisioning/config/encryption.nu [
+    contains-sensitive-data decrypt-config decrypt-config-memory encrypt-config
+    is-encrypted-config load-encrypted-config validate-encryption-config
+]
+use lib_provisioning/kms/client.nu [kms-status]
 
 # Test suite runner
 export def run-encryption-tests [

nulib/lib_provisioning/config/loader/test.nu

@@ -5,8 +5,9 @@
 # Configuration Loader - Testing and Interpolation Functions
 # Provides testing utilities for configuration loading and interpolation
 
-use ../interpolators.nu *
-use ../validators.nu *
+# Selective imports (ADR-025 Phase 3 Layer 2).
+# config/interpolators star-import was dead — dropped.
+use lib_provisioning/config/validators.nu [validate-interpolation]
 
 # Test interpolation with sample data
 export def test-interpolation [

nulib/lib_provisioning/extensions/tests/test_cache.nu

@@ -1,8 +1,9 @@
 #!/usr/bin/env nu
 # Tests for Extension Cache Module
 
-use ../cache.nu *
-use ../../utils/logger.nu *
+# Selective imports (ADR-025 Phase 3 Layer 2).
+# extensions/cache star-import was dead (no used symbols in this test).
+# utils/logger.nu does not exist — dangling import removed.
 
 # Test cache directory creation
 export def test_cache_dir [] {

nulib/lib_provisioning/extensions/tests/test_discovery.nu

@@ -1,8 +1,12 @@
 #!/usr/bin/env nu
 # Tests for Extension Discovery Module
 
-use ../discovery.nu *
-use ../../utils/logger.nu *
+# Selective imports (ADR-025 Phase 3 Layer 2).
+# utils/logger.nu does not exist — dangling import removed.
+use lib_provisioning/extensions/discovery.nu [
+    discover-local-extensions discover-oci-extensions get-extension-versions
+    list-extensions search-extensions
+]
 
 # Test local extension discovery
 export def test_discover_local [] {

nulib/lib_provisioning/extensions/tests/test_oci_client.nu

@@ -1,8 +1,11 @@
 #!/usr/bin/env nu
 # Tests for OCI Client Module
 
-use ../../oci/client.nu *
-use ../../utils/logger.nu *
+# Selective imports (ADR-025 Phase 3 Layer 2).
+# utils/logger.nu does not exist — dangling import removed.
+use lib_provisioning/oci/client.nu [
+    build-artifact-ref get-oci-config is-oci-available test-oci-connection
+]
 
 # Test OCI configuration loading
 export def test_oci_config [] {