Port indexed objective counters and label compatibility notes

RE-1025. Focused validation: cargo xtask test-group rust-effect-counter. Machine report.

Rust implements caller-indexed wrapping counter increments across12 source cases. Index5 increases one word by1, not five score points; invalid indices preserve the supplied window. Historical enum/report tags remain compatible but now carry explicit score/radio/counter semantic corrections. True counter-enum ownership and larger state lifecycle remain open.