feat(vector): add direct pgvector adapter

harness/tht/adapters/factory.py

@@ -1,7 +1,7 @@
 """Central construction of deployment-specific adapters."""
 
 from tht.adapters.dwh import PostgresDwhAdapter, ThothRestDwhAdapter
-from tht.adapters.vector import LegacyDirectVectorStore, ThothHttpVectorStore
+from tht.adapters.vector import PgVectorStore, ThothHttpVectorStore
 from tht.config import Config, ConfigError
 from tht.db.connection import make_engine
 from tht.ports.dwh import DwhAdapter
@@ -32,13 +32,13 @@ def build_vector_store(cfg: Config, *, require_write: bool = False) -> VectorSto
 
     match resource.type:
         case "pgvector_direct":
-            if require_write:
+            reader = resource.reader or resource.connection
+            if require_write and resource.writer is None:
                 raise ConfigError("Vector writer non configurato per pgvector_direct")
-            dim = cfg.embeddings.dim if cfg.embeddings is not None else 768
-            return LegacyDirectVectorStore(
-                make_engine(resource.connection),
-                schema=resource.connection.db_schema,
-                dim=dim,
+            return PgVectorStore(
+                reader,
+                resource.writer,
+                expected_dimension=cfg.embeddings.dim if cfg.embeddings is not None else None,
             )
         case "thoth_vector_http":
             if require_write and resource.writer is None:
@@ -60,15 +60,19 @@ def build_vector_loader(cfg: Config, collection: str):
     if cfg.embeddings is None:
         raise ConfigError("Embeddings non configurati")
 
-    if resource.type == "thoth_vector_http" and resource.writer is not None and (
-        cfg.profile == "workstation" or resource.direct is None
+    if (
+        resource.type == "thoth_vector_http"
+        and resource.writer is not None
+        and (cfg.profile == "workstation" or resource.direct is None)
     ):
         from tht.vectorstore.rest_writer import RestVectorWriter
 
         return RestVectorWriter(VectorRestClient(resource.writer), table=collection)
 
     connection = (
-        resource.connection if resource.type == "pgvector_direct" else resource.direct
+        resource.writer or resource.connection
+        if resource.type == "pgvector_direct"
+        else resource.direct
     )
     if connection is None:
         raise ConfigError("Vector writer non configurato")