eval_all: hash-keyed result cache (--cache-dir, --no-cache); README: bit-ordering scope rules; docs/ISA.md: opcode reference and end-to-end tutorial; docs/float-pipeline.md: composition gap notes

Cleanup pass: README accuracy, dead-code removal, CPU coverage

Add CPU program suite and fix CALL / V-flag handling

Add 18 prebuilt variants and unified eval harness