refactor(ai,java): author voRequest/voResponse columns; remove deriveTraceFields + preFreeze hook

The AI-trace design changed: trace entities now AUTHOR their typed
voRequest/voResponse jsonb columns explicitly instead of deriving them by
injecting synthetic field.object nodes into the loaded metadata tree at load
time. This mirrors the TypeScript reference revert and removes the load-time
metadata mutation entirely.

Removed (the derivation + its generic load-time mutation hook):
- LlmTraceFieldDeriver + its test + trace-derive.yaml fixture (metadata).
- The generic preFreeze loader option on MetaDataLoader (field, setPreFreeze,
  the 4-arg fromUris overload, and the in-load invocation after
  resolvePendingExtends) — MetaDataLoader.java is byte-restored to its
  pre-hook state.
- The deriveTraceFields pre-pass call in AbstractMetaDataMojo (meta:gen).
- The redundant PromptTemplate.getPayloadRef() override added for the deriver
  (the base MetaTemplate.getPayloadRef() is identical and is what every
  generator already calls).

Kept (these never mutate metadata):
- The OMDB recorder (omdb .../manager/db/ai/).
- LlmTraceHelperGenerator (codegen-spring record<Entity> generator) — it
  already carries its own local LLM_CALL_BASE constant, no deriver dependency.
- @responseRef stays first-class cross-port vocabulary (registry manifest
  untouched).

Tests now author the columns instead of relying on derivation:
- integration meta.ai-trace.yaml restored to the Slice-1 authored shape
  (hand-declared voResponse field.object; no template.prompt, no GreetingRequest).
- LlmCallTraceRoundTripTest uses the plain fromUris (no deriver hook); DDL
  restored to voResponse-only.
- The codegen-spring compile-run fixture already authored voResponse/voRequest,
  so it needed no change.

Verified: metadata 983/0/0; codegen-spring 144/0/0 (incl. GeneratedTraceHelper
compile-run); RegistryManifestConformanceTest 3/0/0; integration
LlmCallTraceRoundTripTest 2/2 against real Postgres (authored voResponse jsonb
persisted end-to-end, no derivation).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: dmealing

server/java/integration-tests/src/test/java/com/metaobjects/integration/LlmCallTraceRoundTripTest.java

@@ -1,7 +1,6 @@
 package com.metaobjects.integration;
 
 import com.metaobjects.loader.MetaDataLoader;
-import com.metaobjects.loader.ai.LlmTraceFieldDeriver;
 import com.metaobjects.loader.uri.URIHelper;
 import com.metaobjects.manager.ObjectConnection;
 import com.metaobjects.manager.db.ObjectManagerDB;
@@ -209,12 +208,7 @@ private static MetaDataLoader loadAiTraceMetadata() {
         Path libraryYaml = findRepoFile("library/ai/llm-call.yaml");
         URI libUri = URIHelper.toURI("model:file:" + libraryYaml.toAbsolutePath());
         URI entityUri = URIHelper.toURI("model:resource:meta.ai-trace.yaml");
-        // Wire the AI-trace deriver as a preFreeze hook: voRequest/voResponse are
-        // NOT authored in the fixture — they are derived in-load from the prompt's
-        // @payloadRef/@responseRef, so the OMDB runtime sees the typed jsonb
-        // columns (Slice 3, the metadata-driven-runtime divergence from TS).
-        return MetaDataLoader.fromUris("test-ai-trace", List.of(libUri, entityUri),
-            null, LlmTraceFieldDeriver::deriveTraceFields);
+        return MetaDataLoader.fromUris("test-ai-trace", List.of(libUri, entityUri));
     }
 
     /** Walk up from the working dir to locate a repo-relative file. */
@@ -251,7 +245,6 @@ private static void provisionSchema(PostgresContainer pg) throws SQLException {
                     + "  \"startedAt\" timestamp,\n"
                     + "  \"llmRequest\" jsonb,\n"
                     + "  \"llmResponse\" jsonb,\n"
-                    + "  \"voRequest\" jsonb,\n"
                     + "  \"voResponse\" jsonb\n"
                     + ")");
         }

server/java/integration-tests/src/test/resources/meta.ai-trace.yaml

@@ -1,22 +1,10 @@
 # Test-only trace entity for the AI-trace recorder PG round-trip.
 # Extends the SHIPPED metaobjects::ai::LlmCallBase (loaded from
-# library/ai/llm-call.yaml). The typed voRequest/voResponse jsonb columns are
-# NOT declared here — they are DERIVED by LlmTraceFieldDeriver (Slice 3) from the
-# nested template.prompt's @payloadRef/@responseRef when the loader runs with the
-# deriver wired as a preFreeze hook. This proves derivation reaches the
-# metadata-driven OMDB runtime (the Java-specific divergence from the TS
-# codegen-only reference).
+# library/ai/llm-call.yaml) and adds a typed voResponse jsonb column.
 metadata:
   package: metaobjects::ai
   children:
-    # Typed request payload VO (referenced by @payloadRef → derived voRequest).
-    - object.value:
-        name: GreetingRequest
-        object: com.metaobjects.object.value.ValueObject
-        children:
-          - field.string: { name: prompt }
-
-    # Typed response VO (referenced by @responseRef → derived voResponse).
+    # Typed value object stored in the voResponse jsonb column.
     - object.value:
         name: GreetingResponse
         object: com.metaobjects.object.value.ValueObject
@@ -25,15 +13,16 @@ metadata:
           - field.int:    { name: score,    column: score }
 
     # Concrete trace entity: inherits the 18 LlmCallBase fields, declares its
-    # table + primary identity + a template.prompt. The deriver injects
-    # voRequest/voResponse field.object jsonb columns from the prompt refs.
+    # table + primary identity + a typed voResponse jsonb column (@objectRef +
+    # @storage:jsonb — the owned-object typed-jsonb codec path).
     - object.entity:
         name: GreetingCall
         extends: metaobjects::ai::LlmCallBase
         children:
           - source.rdb:       { table: llm_call, role: primary }
           - identity.primary: { name: primary, fields: ["spanId"] }
-          - template.prompt:
-              name: greet
-              payloadRef: metaobjects::ai::GreetingRequest
-              responseRef: metaobjects::ai::GreetingResponse
+          - field.object:
+              name: voResponse
+              column: voResponse
+              storage: jsonb
+              objectRef: metaobjects::ai::GreetingResponse

server/java/maven-plugin/src/main/java/com/metaobjects/mojo/AbstractMetaDataMojo.java

@@ -86,14 +86,6 @@ public void execute() throws MojoExecutionException, MojoFailureException
 
         MetaDataLoader loader = createLoader(projectClassLoader);
 
-        // AI-trace pre-pass: derive typed voRequest/voResponse jsonb columns onto
-        // LlmCallBase-derived entities so the trace-helper generator (and any
-        // entity/schema codegen) sees them without the author restating them.
-        // Idempotent + a no-op for projects with no trace entities. The loader is
-        // already loaded here (no hard freeze in Java); generators re-read children
-        // fresh, so post-load derivation is sufficient for codegen.
-        com.metaobjects.loader.ai.LlmTraceFieldDeriver.deriveTraceFields( loader );
-
         List<Generator> generatorImpls = buildGenerators( projectClassLoader, null );
 
         executeGenerators( loader, generatorImpls );

server/java/metadata/src/main/java/com/metaobjects/loader/MetaDataLoader.java

@@ -110,15 +110,6 @@ public class MetaDataLoader implements LoaderConfigurable {
     // ClassLoader used for resolving metadata-referenced Java classes.
     private ClassLoader metaDataClassLoader = null;
 
-    // Optional pre-freeze enrichment hook. Mirrors the TypeScript loader's
-    // generic `preFreeze` option: a callback that runs inside {@link #load} once
-    // the tree is parsed and {@code extends} refs are resolved, but before the
-    // validation passes. This is the designated injection point for programmatic
-    // tree enrichment (e.g. codegen/runtime pre-passes that DERIVE additional
-    // nodes from validated metadata). The injected nodes participate in the
-    // subsequent validation passes. Null by default (no enrichment).
-    private java.util.function.Consumer<MetaDataLoader> preFreeze = null;
-
     // v6.0.0: Unified registry
     private MetaDataRegistry typeRegistry = null;
     private MetaDataLoaderRegistry loaderRegistry = null;
@@ -400,26 +391,9 @@ public static MetaDataLoader fromUris(String name, List<URI> uris) {
      * @return a fully-initialized loader with all URIs loaded
      */
     public static MetaDataLoader fromUris(String name, List<URI> uris, LoaderOptions opts) {
-        return fromUris(name, uris, opts, null);
-    }
-
-    /**
-     * Build + load with a pre-freeze enrichment hook (see {@link #setPreFreeze}).
-     * The hook runs in-load (after extends-resolution, before validation), so any
-     * derived nodes are validated and registered atomically with this build.
-     *
-     * @param name      the loader name
-     * @param uris      model URIs to load
-     * @param opts      loader options (may be {@code null} for defaults)
-     * @param preFreeze pre-freeze enrichment hook (may be {@code null})
-     * @return a fully-initialized loader with all URIs loaded
-     */
-    public static MetaDataLoader fromUris(String name, List<URI> uris, LoaderOptions opts,
-                                          java.util.function.Consumer<MetaDataLoader> preFreeze) {
         MetaDataLoader loader = (opts == null)
             ? createManual(false, name)
             : new MetaDataLoader(opts, SUBTYPE_MANUAL, name);
-        if (preFreeze != null) loader.setPreFreeze(preFreeze);
         try {
             loader.init();
             List<MetaDataSource> sources = new ArrayList<>(uris.size());
@@ -698,19 +672,6 @@ public ClassLoader getMetaDataClassLoader() {
         return getDefaultMetaDataClassLoader();
     }
 
-    /**
-     * Register a pre-freeze enrichment hook (mirrors the TS loader's generic
-     * {@code preFreeze} option). The hook runs inside {@link #load} after
-     * {@code extends} refs are resolved and before the validation passes, so any
-     * nodes it injects are validated like hand-authored ones. Fluent; pass
-     * {@code null} to clear. Must be set before {@link #load} runs.
-     */
-    @SuppressWarnings("unchecked")
-    public <T extends MetaDataLoader> T setPreFreeze(java.util.function.Consumer<MetaDataLoader> hook) {
-        this.preFreeze = hook;
-        return (T) this;
-    }
-
     ///////////////////////////////////////////////////////////////////////
     // Source URIs (H3a Task 5: lifted from SimpleLoader)
 
@@ -1289,14 +1250,6 @@ public MetaDataLoader load(List<MetaDataSource> sources) {
         // becomes ERR_UNRESOLVED_SUPER.
         resolvePendingExtends();
 
-        // Pre-freeze enrichment hook (mirrors TS): runs after extends-resolution
-        // and before validation, so DERIVED nodes (e.g. AI-trace voRequest/
-        // voResponse jsonb columns) are visible to the validation passes and to
-        // every downstream reader (codegen + runtime) just like authored nodes.
-        if (preFreeze != null) {
-            preFreeze.accept(this);
-        }
-
         // Run post-load validation passes after all sources in this batch are parsed.
         // Fires both when called from init() (via loadSourceURIsIfPresent) and when
         // called directly by tests or the conformance runner. The loader handle is

server/java/metadata/src/main/java/com/metaobjects/loader/ai/LlmTraceFieldDeriver.java

@@ -77,11 +77,4 @@ public String getResponseRef() {
             ? getMetaAttr(ATTR_RESPONSE_REF, false).getValueAsString()
             : null;
     }
-
-    /** Returns the raw value of {@code @payloadRef}, or {@code null} if absent. */
-    public String getPayloadRef() {
-        return hasMetaAttr(ATTR_PAYLOAD_REF, false)
-            ? getMetaAttr(ATTR_PAYLOAD_REF, false).getValueAsString()
-            : null;
-    }
 }