Implements the async-embedding pipeline's worker side:
- php/Jobs/EmbedMemory.php — Laravel Job that calls BrainService::embed()
+ qdrantUpsert() and sets indexed_at on success
- php/Migrations/…_add_indexed_at_to_brain_memories.php — nullable
timestamp + index, portable across pgsql/mariadb (hasColumn guard)
- BrainMemory: +indexed_at fillable + datetime cast + PHPDoc
- BrainService: qdrantUpsert() private→public so the Job can use it;
elasticIndex() stub added (to be implemented by the ES ticket)
- php/tests/Feature/Jobs/EmbedMemoryTest.php — Pest tests for success
path and Qdrant-failure path
Co-authored-by: Codex <noreply@openai.com>
Closes tasks.lthn.sh/view.php?id=56
