Deduplicate artifact bytes and deliver files by authenticated hash

README.md

@@ -129,6 +129,13 @@ stopping games; activation uses the same occupancy and concurrency gates as
 lifecycle operations. Agent before images preserve exact rollback bytes and
 operation history.
 
+Artifact bodies are stored once by SHA-256 in SQLite. Versions, staging plans,
+rollback snapshots and launch commands reference those shared bytes. The first
+startup after this upgrade backfills existing rows transactionally; preserve the
+data-directory backup when upgrading. Current agents fetch assigned artifacts
+from an authenticated endpoint and verify the hash. Older agents continue to
+receive inline content until their automatic update completes.
+
 T5 Zombies uses `t5sp` and `dedicated_sp.cfg`; T6 uses `t6zm` and
 `dedicated_zm.cfg`. Map selection generates `electric_cherry_map.cfg`, loaded
 after the main config. T6 variants retain their distinct catalog selections.