fix: address remaining CodeRabbit review findings

- Add SQLERROR/OSERROR guards to enterprise-19 ALTER SYSTEM REGISTER
- Update README directory tree to reflect new layout

Author: rophy

tests/README.md

@@ -114,27 +114,30 @@ archives are gitignored (except `example-*` bootstrapping fixtures).
 ```
 tests/
   conftest.py                         # Fixture discovery + SQL tag → pytest marker mapping
-  test_fixtures.py                    # Redo log regression tests
-  test_e2e.py                    # End-to-end tests (requires live Oracle)
   pytest.ini                          # Marker registration
 
+  environments/                       # Oracle container environments
+    free-23/                          # Oracle Free 23c
+    xe-21/                            # Oracle XE 21c
+    xe-21-official/                   # Oracle XE 21c (official image)
+    enterprise-19/                    # Oracle Enterprise 19c
+    rac/                              # Oracle RAC (VM-based)
+
   fixtures/                           # Local fixture cache (mostly gitignored)
+    test_fixtures.py                  # Redo log regression tests
     <scenario>.tar.gz                 # Compressed fixture (gitignored, generated by `make fixtures`)
     <scenario>/                       # Extracted (gitignored)
       redo/*.dbf
       schema/TEST-chkpt-<scn>.json
       expected/output.json
 
   sql/                                # SQL test infrastructure (requires live Oracle)
+    test_e2e.py                       # End-to-end tests (requires live Oracle)
     inputs/                           # SQL scenarios
       basic-crud.sql                  # Single-file format
       example/                        # Split format (setup.sql + test.sql)
         setup.sql
         test.sql
-    environments/                     # Oracle container environments
-      free-23/                        # Oracle Free 23c
-      xe-21/                          # Oracle XE 21c
-      xe-21-official/                 # Oracle XE 21c (official image)
     scripts/
       generate.sh                     # Generate + validate one fixture
       compare.py                      # OLR vs LogMiner comparison
@@ -146,7 +149,7 @@ tests/
         rac.sh                        # RAC: SSH + podman exec to RAC VM
     generated/                        # Locally generated fixtures (gitignored)
 
-  debezium/                           # Debezium twin-test (OLR vs LogMiner adapters)
+  dbz-twin/                           # Debezium twin-test (OLR vs LogMiner adapters)
 ```
 
 ## Input Formats

tests/environments/enterprise-19/oracle-init/01-setup.sh

@@ -8,7 +8,10 @@ set -e
 
 # Register PDB service with listener (needed for external connections)
 sqlplus -S / as sysdba <<'SQL'
+WHENEVER SQLERROR EXIT SQL.SQLCODE
+WHENEVER OSERROR EXIT FAILURE
 ALTER SYSTEM REGISTER;
+EXIT
 SQL
 
 # Enable supplemental logging (idempotent)