Fix child workflow codec mismatch when args contain PHP-only values

`async()` produces a `SerializableClosure` which Avro cannot round-trip.
The child run inherits the parent's `payload_codec` but `serializeWithCodec`
silently serialized the closure-carrying array as zero-length Avro bytes,
so on child start the codec tag said "avro" while the blob was empty/invalid
— the v2 engine failed the run with `CodecDecodeException`.

Same pattern as `a71304a` (legacy `__callStatic` path) extended to the
explicit-codec `serializeWithCodec` path:

- Serializer: new `chooseCodecForData(?preferred, data): string` helper that
  falls back to `workflow-serializer-y` when Avro is preferred but the data
  carries PHP-only objects. Callers that stamp `payload_codec` alongside a
  blob must use this helper so the row's codec tag matches the bytes.
- WorkflowExecutor::scheduleChildWorkflow: pick the child run's codec via
  the helper before serializing, so `workflow_runs.payload_codec` reflects
  the actual wire format.
- WorkflowExecutor::recordWorkflowStartCommand: same treatment for the
  `workflow_commands.payload_codec` column.

Also fill in missing columns in the V2ConfiguredCoreModelsTest custom
tables (`search_attributes`, `namespace`, `message_cursor_position`,
`run_timeout_seconds`, `execution_deadline_at`, `run_deadline_at`, plus
new `namespace`/`execution_timeout_seconds`/`last_message_sequence` on the
instance-alias table and `namespace` on the task-alias table) so the
test's alias models accept every column the v2 engine writes.

Clears five MySQL failures on workflow v2 CI under #399:
  * testCoreRuntimeUsesConfiguredInstanceRunAndTaskModels
  * testAsyncHelperRunsStraightLineClosureAsDurableChildWorkflow
  * and three related cascading failures that depended on async child
    workflows completing.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: durable-workflow-ops

src/Serializers/Serializer.php

@@ -126,6 +126,25 @@ public static function serializeWithCodec(?string $codec, $data): string
         return $class::serialize($data);
     }
 
+    /**
+     * Pick the codec name actually used to serialize a payload. If the
+     * preferred codec is Avro but the value contains PHP-only objects
+     * (SerializableClosure, resources, arbitrary objects Avro cannot encode),
+     * fall back to the legacy `workflow-serializer-y` codec so the payload
+     * round-trips. Callers that store a payload_codec column alongside the
+     * blob must use the codec returned here, not the preferred input.
+     */
+    public static function chooseCodecForData(?string $preferred, mixed $data): string
+    {
+        $preferredCodec = CodecRegistry::resolve($preferred);
+
+        if ($preferredCodec === Avro::class && self::containsPhpOnlyValue($data)) {
+            return 'workflow-serializer-y';
+        }
+
+        return CodecRegistry::canonicalize($preferred);
+    }
+
     /**
      * Unserialize using an explicit codec name.
      */

src/V2/Support/WorkflowExecutor.php

@@ -1515,9 +1515,14 @@ private function scheduleChildWorkflow(
         // arguments (next line) match the codec stamped on the child run.
         // Falling back to the package default when the parent has none
         // keeps pre-pinned parents working.
-        $childCodec = is_string($run->payload_codec) && $run->payload_codec !== ''
+        $preferredChildCodec = is_string($run->payload_codec) && $run->payload_codec !== ''
             ? $run->payload_codec
             : CodecRegistry::defaultCodec();
+        // When the child arguments carry PHP-only values (e.g. a
+        // SerializableClosure produced by async()), Avro cannot round-trip
+        // them. Pick the actually-used codec so the row's `payload_codec`
+        // matches what the blob was serialized with.
+        $childCodec = Serializer::chooseCodecForData($preferredChildCodec, $metadata->arguments);
         $serializedChildArguments = Serializer::serializeWithCodec($childCodec, $metadata->arguments);
         StructuralLimits::guardPayloadSize($serializedChildArguments);
 
@@ -2499,8 +2504,11 @@ private function recordWorkflowStartCommand(
                     'target_scope' => 'instance',
                     'status' => CommandStatus::Accepted->value,
                     'outcome' => CommandOutcome::StartedNew->value,
-                    'payload_codec' => $sourceRun->payload_codec ?? CodecRegistry::defaultCodec(),
-                    'payload' => Serializer::serializeWithCodec($sourceRun->payload_codec, $arguments),
+                    'payload_codec' => $startCommandCodec = Serializer::chooseCodecForData(
+                        $sourceRun->payload_codec ?? CodecRegistry::defaultCodec(),
+                        $arguments,
+                    ),
+                    'payload' => Serializer::serializeWithCodec($startCommandCodec, $arguments),
                     'accepted_at' => $recordedAt,
                     'applied_at' => $recordedAt,
                     'created_at' => $recordedAt,

tests/Feature/V2/V2ConfiguredCoreModelsTest.php

@@ -77,17 +77,24 @@ private function createConfiguredInstancesTable(): void
                 ->primary();
             $table->string('workflow_class');
             $table->string('workflow_type');
+            $table->string('namespace')
+                ->nullable()
+                ->index();
             $table->string('business_key', 191)
                 ->nullable();
             $table->json('visibility_labels')
                 ->nullable();
             $table->json('memo')
                 ->nullable();
+            $table->unsignedInteger('execution_timeout_seconds')
+                ->nullable();
             $table->string('current_run_id', 26)
                 ->nullable()
                 ->index();
             $table->unsignedInteger('run_count')
                 ->default(0);
+            $table->unsignedInteger('last_message_sequence')
+                ->default(0);
             $table->timestamp('reserved_at', 6)
                 ->nullable();
             $table->timestamp('started_at', 6)
@@ -106,12 +113,17 @@ private function createConfiguredRunsTable(): void
             $table->unsignedInteger('run_number');
             $table->string('workflow_class');
             $table->string('workflow_type');
+            $table->string('namespace')
+                ->nullable()
+                ->index();
             $table->string('business_key', 191)
                 ->nullable();
             $table->json('visibility_labels')
                 ->nullable();
             $table->json('memo')
                 ->nullable();
+            $table->json('search_attributes')
+                ->nullable();
             $table->string('status');
             $table->string('closed_reason')
                 ->nullable();
@@ -131,6 +143,14 @@ private function createConfiguredRunsTable(): void
                 ->default(0);
             $table->unsignedInteger('last_command_sequence')
                 ->default(0);
+            $table->unsignedInteger('message_cursor_position')
+                ->default(0);
+            $table->unsignedInteger('run_timeout_seconds')
+                ->nullable();
+            $table->timestamp('execution_deadline_at', 6)
+                ->nullable();
+            $table->timestamp('run_deadline_at', 6)
+                ->nullable();
             $table->timestamp('started_at', 6)
                 ->nullable();
             $table->timestamp('closed_at', 6)
@@ -156,6 +176,9 @@ private function createConfiguredTasksTable(): void
                 ->primary();
             $table->string('workflow_run_id', 26)
                 ->index();
+            $table->string('namespace')
+                ->nullable()
+                ->index();
             $table->string('task_type');
             $table->string('status');
             $table->json('payload')