feat(playbook): version generated playbooks

apps/api/src/db/base.py

@@ -207,9 +207,24 @@ async def init_db() -> None:
                 ADD COLUMN IF NOT EXISTS trust_score FLOAT NOT NULL DEFAULT 0.3,
                 ADD COLUMN IF NOT EXISTS requires_approval_level VARCHAR(20) NOT NULL DEFAULT 'auto',
                 ADD COLUMN IF NOT EXISTS stateful_targets JSONB NOT NULL DEFAULT '[]',
-                ADD COLUMN IF NOT EXISTS requires_pre_backup BOOLEAN NOT NULL DEFAULT FALSE;
+                ADD COLUMN IF NOT EXISTS requires_pre_backup BOOLEAN NOT NULL DEFAULT FALSE,
+                ADD COLUMN IF NOT EXISTS version INTEGER NOT NULL DEFAULT 1,
+                ADD COLUMN IF NOT EXISTS parent_playbook_id VARCHAR(36),
+                ADD COLUMN IF NOT EXISTS supersedes_playbook_id VARCHAR(36),
+                ADD COLUMN IF NOT EXISTS version_reason TEXT;
             """)
         )
+        await conn.execute(text(
+            "CREATE INDEX IF NOT EXISTS ix_playbook_lineage "
+            "ON playbooks(parent_playbook_id, version);"
+        ))
+        await conn.execute(text(
+            "CREATE INDEX IF NOT EXISTS ix_playbook_supersedes "
+            "ON playbooks(supersedes_playbook_id) WHERE supersedes_playbook_id IS NOT NULL;"
+        ))
+        await conn.execute(text(
+            "UPDATE playbooks SET parent_playbook_id = playbook_id WHERE parent_playbook_id IS NULL;"
+        ))
 
         # 2026-04-15 ogt + Claude Sonnet 4.6（亞太）: Phase 4 8D 感官升級
         # ADR-084: EvidenceSnapshot 加入 Phase 4 動態異常上下文（anomaly_context）