revert: restore memory_entity/memory_edge table names

knowledge_* namespace reserved for future agentic learning tables.
memory_* namespace used for facts, events, and entity graph.

- knowledge_node → memory_entity (reverted)
- knowledge_edge → memory_edge (reverted)
- Old provenance DAG (child_sha/parent_sha) renamed to
  memory_edge_provenance via migration 009
- Kept: runtime queries in versioning.rs, UUID casts, init_schema additions

crates/mem-store/migrations/008_phase3_compaction.sql

@@ -9,8 +9,8 @@ CREATE TABLE IF NOT EXISTS exact_dedup_record (
     project_id VARCHAR(255) NOT NULL,
     
     -- Source and target edges
-    source_edge_id UUID NOT NULL REFERENCES knowledge_edge(id) ON DELETE CASCADE,
-    target_edge_id UUID NOT NULL REFERENCES knowledge_edge(id) ON DELETE CASCADE,
+    source_edge_id UUID NOT NULL REFERENCES memory_edge(id) ON DELETE CASCADE,
+    target_edge_id UUID NOT NULL REFERENCES memory_edge(id) ON DELETE CASCADE,
     
     -- Match criteria (all must match for exact dedup)
     source_match BOOLEAN NOT NULL,
@@ -51,8 +51,8 @@ CREATE TABLE IF NOT EXISTS stale_gc_record (
     project_id VARCHAR(255) NOT NULL,
     
     -- Entity or edge marked for GC
-    entity_id UUID REFERENCES knowledge_node(id) ON DELETE CASCADE,
-    edge_id UUID REFERENCES knowledge_edge(id) ON DELETE CASCADE,
+    entity_id UUID REFERENCES memory_entity(id) ON DELETE CASCADE,
+    edge_id UUID REFERENCES memory_edge(id) ON DELETE CASCADE,
     
     -- Staleness criteria
     age_days INT NOT NULL,
@@ -96,8 +96,8 @@ CREATE TABLE IF NOT EXISTS semantic_dedup_record (
     project_id VARCHAR(255) NOT NULL,
     
     -- Source and target edges
-    source_edge_id UUID NOT NULL REFERENCES knowledge_edge(id) ON DELETE CASCADE,
-    target_edge_id UUID NOT NULL REFERENCES knowledge_edge(id) ON DELETE CASCADE,
+    source_edge_id UUID NOT NULL REFERENCES memory_edge(id) ON DELETE CASCADE,
+    target_edge_id UUID NOT NULL REFERENCES memory_edge(id) ON DELETE CASCADE,
     
     -- Pre-filter score (0-1, eliminates 60-70% of candidates)
     prefilter_score FLOAT NOT NULL,
@@ -119,7 +119,7 @@ CREATE TABLE IF NOT EXISTS semantic_dedup_record (
     
     -- Merge strategy (if auto-merged)
     merge_strategy VARCHAR(50),  -- 'keep_superset', 'keep_newer', 'keep_higher_confidence'
-    merged_edge_id UUID REFERENCES knowledge_edge(id) ON DELETE SET NULL,
+    merged_edge_id UUID REFERENCES memory_edge(id) ON DELETE SET NULL,
     
     -- Metadata
     detected_at TIMESTAMPTZ DEFAULT NOW(),