chore: harden knowledge graph storage and clear common clippy warnings

Enforce stable 1:1 entity embeddings, relationship endpoint auth, and
user-scoped deletes; align schemas/migrations and resolve common crate
clippy findings.

common/schemas/knowledge_entity.surql

@@ -1,6 +1,6 @@
 # Defines the schema for the 'knowledge_entity' table.
 
-DEFINE TABLE IF NOT EXISTS knowledge_entity SCHEMALESS;
+DEFINE TABLE IF NOT EXISTS knowledge_entity SCHEMAFULL;
 
 # Standard fields
 DEFINE FIELD IF NOT EXISTS created_at ON knowledge_entity TYPE datetime;
@@ -22,5 +22,6 @@ DEFINE FIELD IF NOT EXISTS user_id ON knowledge_entity TYPE string;
 -- DEFINE INDEX IF NOT EXISTS idx_embedding_entities ON knowledge_entity FIELDS embedding HNSW DIMENSION 1536;
 DEFINE INDEX IF NOT EXISTS knowledge_entity_source_id_idx ON knowledge_entity FIELDS source_id;
 DEFINE INDEX IF NOT EXISTS knowledge_entity_user_id_idx ON knowledge_entity FIELDS user_id;
+DEFINE INDEX IF NOT EXISTS knowledge_entity_user_source_idx ON knowledge_entity FIELDS user_id, source_id;
 DEFINE INDEX IF NOT EXISTS knowledge_entity_entity_type_idx ON knowledge_entity FIELDS entity_type;
 DEFINE INDEX IF NOT EXISTS knowledge_entity_created_at_idx ON knowledge_entity FIELDS created_at;

common/schemas/knowledge_entity_embedding.surql

@@ -7,6 +7,7 @@ DEFINE TABLE IF NOT EXISTS knowledge_entity_embedding SCHEMAFULL;
 DEFINE FIELD IF NOT EXISTS created_at ON knowledge_entity_embedding TYPE datetime;
 DEFINE FIELD IF NOT EXISTS updated_at ON knowledge_entity_embedding TYPE datetime;
 DEFINE FIELD IF NOT EXISTS user_id ON knowledge_entity_embedding TYPE string;
+DEFINE FIELD IF NOT EXISTS source_id ON knowledge_entity_embedding TYPE string;
 
 -- Custom fields
 DEFINE FIELD IF NOT EXISTS entity_id ON knowledge_entity_embedding TYPE record<knowledge_entity>;
@@ -14,5 +15,6 @@ DEFINE FIELD IF NOT EXISTS embedding ON knowledge_entity_embedding TYPE array<fl
 
 -- Indexes
 -- DEFINE INDEX IF NOT EXISTS idx_embedding_knowledge_entity_embedding ON knowledge_entity_embedding FIELDS embedding HNSW DIMENSION 1536;
-DEFINE INDEX IF NOT EXISTS knowledge_entity_embedding_entity_id_idx ON knowledge_entity_embedding FIELDS entity_id;
+DEFINE INDEX IF NOT EXISTS knowledge_entity_embedding_entity_id_idx ON knowledge_entity_embedding FIELDS entity_id UNIQUE;
 DEFINE INDEX IF NOT EXISTS knowledge_entity_embedding_user_id_idx ON knowledge_entity_embedding FIELDS user_id;
+DEFINE INDEX IF NOT EXISTS knowledge_entity_embedding_source_id_idx ON knowledge_entity_embedding FIELDS source_id;

common/schemas/relates_to.surql

@@ -1,18 +1,16 @@
 # Defines the 'relates_to' edge table for KnowledgeRelationships.
 # Edges connect nodes, in this case knowledge_entity records.
 
-# Define the edge table itself, enforcing connections between knowledge_entity records
-# SCHEMAFULL requires all fields to be defined, maybe start with SCHEMALESS if metadata might vary
-DEFINE TABLE IF NOT EXISTS relates_to SCHEMALESS TYPE RELATION FROM knowledge_entity TO knowledge_entity;
+DEFINE TABLE IF NOT EXISTS relates_to SCHEMAFULL TYPE RELATION FROM knowledge_entity TO knowledge_entity;
+
+DEFINE FIELD IF NOT EXISTS in ON relates_to TYPE record<knowledge_entity>;
+DEFINE FIELD IF NOT EXISTS out ON relates_to TYPE record<knowledge_entity>;
 
-# Define the metadata field within the edge
 # RelationshipMetadata is a struct, store as object
 DEFINE FIELD IF NOT EXISTS metadata ON relates_to TYPE object;
-
-# Optionally, define fields within the metadata object for stricter schema (requires SCHEMAFULL on table)
-# DEFINE FIELD IF NOT EXISTS metadata.user_id ON relates_to TYPE string;
-# DEFINE FIELD IF NOT EXISTS metadata.source_id ON relates_to TYPE string;
-# DEFINE FIELD IF NOT EXISTS metadata.relationship_type ON relates_to TYPE string;
+DEFINE FIELD IF NOT EXISTS metadata.user_id ON relates_to TYPE string;
+DEFINE FIELD IF NOT EXISTS metadata.source_id ON relates_to TYPE string;
+DEFINE FIELD IF NOT EXISTS metadata.relationship_type ON relates_to TYPE string;
 
 # Add indexes based on query patterns (delete_relationships_by_source_id, get_knowledge_relationships)
 DEFINE INDEX IF NOT EXISTS relates_to_metadata_source_id_idx ON relates_to FIELDS metadata.source_id;