Merge WA4+WA5: Java loader consolidation + conformance gate

WA4 — server/java now has one type-system + loader module (metadata) instead
of the metadata+core split that diverged from TS/C#/Python:
- Move 5 file-IO classes (FileMetaDataLoader, FileLoaderOptions,
  FileMetaDataSources, LocalFileMetaDataSources, URIFileMetaDataSources)
  from core to metadata (FQNs preserved at com.metaobjects.loader.file.*).
- Absorb CoreTypeInitializer into metadata.
- Drop legacy XML I/O (7 classes — XML MetaData/Object Reader/Writer +
  helpers; 1014 LOC removed) — canonical JSON is the only on-disk format.
- Delete the empty IOMetaDataProvider SPI shell.
- Re-point omdb/dynamic/maven-plugin/core-spring/om/omdb-ktx poms off
  metaobjects-core.
- Delete the core module + remove <module>core</module> from server/java/pom.xml.
- Migrate FileMetaDataLoaderTest (10 tests) from core/src/test to metadata.

WA5 — Conformance gate: AlignedVocabularyTest smoke verifies object.entity/
value + source.rdb + @kind/@ROLE:primary+replica + origin.passthrough +
camelCase preservation round-trip in canonical JSON, AND none of the retired
vocabulary (source.dbTable/dbView, object.pojo/map/proxy, @javaruntime)
leaks back out. Conformance ledger audit: 30 entries, zero WA1-WA4 vocabulary
remainders.

Module count 13 -> 12. Reactor green: metadata 625/0/0, all other Java
modules unchanged green. Unblocks the metadata-ktx Kotlin facade.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Author: dmealing

docs/superpowers/plans/2026-05-25-wa4-wa5-loader-consolidation-and-conformance-gate.md

@@ -18,7 +18,7 @@
     <dependencies>
         <dependency>
             <groupId>com.metaobjects</groupId>
-            <artifactId>metaobjects-core</artifactId>
+            <artifactId>metaobjects-metadata</artifactId>
             <version>${project.version}</version>
         </dependency>