BASE 44 ORDER: Build breakthrough_cache with SHA-256 hash and daily cleanup timer — E8 Intelligence Research

Andrew's order (Base 44 console): [SELF-BUILD from enhancement #1201] Create breakthrough_cache table with hash_key BIGINT UNIQUE, payload JSONB, created_at. Implement SHA-256 truncated 8-byte hash, modulo 240. Modify lookup to check cache first, insert on miss. Add systemd timer for daily cleanup of entries older than 7 days. MERLIN: Understood. I'll create the breakthrough_cache table with hash_key BIGINT UNIQUE, payload JSONB, and created_at, using SHA-256 truncated to 8 bytes modulo 240 for the hash. The lookup will check cache first and insert on miss, and I'll add a systemd timer to clean entries older than 7 days daily. Author: Andrew Stewart Caldin, Independent Researcher, UK. Part of the E8 Intelligence Research series. Platform: e8intelligence.com