refactor: rename memory_entity→knowledge_node, knowledge graph edge→knowledge_edge

Resolves table name collision between:
- memory_edge (provenance DAG: child_sha/parent_sha) — KEPT
- knowledge_edge (knowledge graph: source_id/target_id) — NEW NAME

Changes:
- memory_entity → knowledge_node (all .rs + migrations 003-009)
- knowledge graph memory_edge → knowledge_edge
- memory_entity_version → knowledge_node_version
- memory_edge_version → knowledge_edge_version
- Added knowledge_node + knowledge_edge to init_schema()
- Converted versioning.rs from sqlx::query_as! to runtime queries
  (avoids stale sqlx offline cache dependency)
- Fixed UUID cast: $1::UUID for String→UUID column binds
- Fixed column names: source_entity_id→source_id, target_entity_id→target_id

Production DB: knowledge_node + knowledge_edge tables created,
memory_entity VIEW points to knowledge_node for backward compat.

crates/mem-store/migrations/004_auth_schema.sql

@@ -41,53 +41,53 @@ CREATE INDEX IF NOT EXISTS idx_memory_projects_visibility
 -- 2. Add attribution columns to entities
 -- ─────────────────────────────────────────────────────────────────────────────
 
-ALTER TABLE memory_entity ADD COLUMN IF NOT EXISTS (
+ALTER TABLE knowledge_node ADD COLUMN IF NOT EXISTS (
     contributed_by VARCHAR(255),           -- JWT "sub" who added this
     contribution_type VARCHAR(50),         -- "extracted" | "manual" | "inferred"
     contribution_date TIMESTAMPTZ
 );
 
 -- Populate contributed_by with defaults (assume "system" if not present)
-UPDATE memory_entity 
+UPDATE knowledge_node 
 SET contributed_by = 'system' 
 WHERE contributed_by IS NULL;
 
-ALTER TABLE memory_entity 
+ALTER TABLE knowledge_node 
 ALTER COLUMN contributed_by SET NOT NULL;
 
-CREATE INDEX IF NOT EXISTS idx_memory_entity_contributed_by 
-    ON memory_entity(contributed_by);
+CREATE INDEX IF NOT EXISTS idx_knowledge_node_contributed_by 
+    ON knowledge_node(contributed_by);
 
-CREATE INDEX IF NOT EXISTS idx_memory_entity_contribution_date 
-    ON memory_entity(contribution_date) 
+CREATE INDEX IF NOT EXISTS idx_knowledge_node_contribution_date 
+    ON knowledge_node(contribution_date) 
     WHERE contribution_date IS NOT NULL;
 
 -- ─────────────────────────────────────────────────────────────────────────────
 -- 3. Add attribution columns to edges
 -- ─────────────────────────────────────────────────────────────────────────────
 
-ALTER TABLE memory_edge ADD COLUMN IF NOT EXISTS (
+ALTER TABLE knowledge_edge ADD COLUMN IF NOT EXISTS (
     contributed_by VARCHAR(255),           -- JWT "sub" who added this
     contribution_type VARCHAR(50)          -- "extracted" | "inferred"
 );
 
 -- Populate contributed_by with defaults
-UPDATE memory_edge 
+UPDATE knowledge_edge 
 SET contributed_by = 'system' 
 WHERE contributed_by IS NULL;
 
-ALTER TABLE memory_edge 
+ALTER TABLE knowledge_edge 
 ALTER COLUMN contributed_by SET NOT NULL;
 
-CREATE INDEX IF NOT EXISTS idx_memory_edge_contributed_by 
-    ON memory_edge(contributed_by);
+CREATE INDEX IF NOT EXISTS idx_knowledge_edge_contributed_by 
+    ON knowledge_edge(contributed_by);
 
 -- ─────────────────────────────────────────────────────────────────────────────
 -- 4. Add project_id to entities and edges (optional, for faster filtering)
 -- ─────────────────────────────────────────────────────────────────────────────
 
--- ALTER TABLE memory_entity ADD COLUMN IF NOT EXISTS project_id VARCHAR(255);
--- ALTER TABLE memory_edge ADD COLUMN IF NOT EXISTS project_id VARCHAR(255);
+-- ALTER TABLE knowledge_node ADD COLUMN IF NOT EXISTS project_id VARCHAR(255);
+-- ALTER TABLE knowledge_edge ADD COLUMN IF NOT EXISTS project_id VARCHAR(255);
 -- 
 -- Note: Deferred. Can use project info from path/source instead.
 
@@ -102,7 +102,7 @@ SELECT
     COUNT(*) as entity_count,
     MAX(contribution_date) as last_contribution,
     ARRAY_AGG(DISTINCT contribution_type) as contribution_types
-FROM memory_entity
+FROM knowledge_node
 WHERE contribution_date IS NOT NULL
 GROUP BY contributed_by;
 
@@ -112,7 +112,7 @@ SELECT
     contributed_by,
     COUNT(*) as count,
     MAX(contribution_date) as latest
-FROM memory_entity
+FROM knowledge_node
 WHERE contribution_date > CURRENT_TIMESTAMP - INTERVAL '7 days'
 GROUP BY contributed_by;
 
@@ -129,12 +129,12 @@ GROUP BY contributed_by;
 -- DROP INDEX IF EXISTS idx_memory_projects_visibility;
 -- DROP TABLE IF EXISTS memory_projects;
 -- 
--- DROP INDEX IF EXISTS idx_memory_entity_contributed_by;
--- DROP INDEX IF EXISTS idx_memory_entity_contribution_date;
--- ALTER TABLE memory_entity DROP COLUMN IF EXISTS contributed_by;
--- ALTER TABLE memory_entity DROP COLUMN IF EXISTS contribution_type;
--- ALTER TABLE memory_entity DROP COLUMN IF EXISTS contribution_date;
+-- DROP INDEX IF EXISTS idx_knowledge_node_contributed_by;
+-- DROP INDEX IF EXISTS idx_knowledge_node_contribution_date;
+-- ALTER TABLE knowledge_node DROP COLUMN IF EXISTS contributed_by;
+-- ALTER TABLE knowledge_node DROP COLUMN IF EXISTS contribution_type;
+-- ALTER TABLE knowledge_node DROP COLUMN IF EXISTS contribution_date;
 -- 
--- DROP INDEX IF EXISTS idx_memory_edge_contributed_by;
--- ALTER TABLE memory_edge DROP COLUMN IF EXISTS contributed_by;
--- ALTER TABLE memory_edge DROP COLUMN IF EXISTS contribution_type;
+-- DROP INDEX IF EXISTS idx_knowledge_edge_contributed_by;
+-- ALTER TABLE knowledge_edge DROP COLUMN IF EXISTS contributed_by;
+-- ALTER TABLE knowledge_edge DROP COLUMN IF EXISTS contribution_type;