Selectivity Adds Practical Examples for CSV and JSON Lines

Selectivity now has three more runnable examples showing how a developer can put the Go reducer to work. Each pairs a generated input with a Python predicate and a saved run from the released 0.1.1 binary. The engine has not changed. The new material makes the contract easier to inspect: define the behavior worth keeping, classify invalid candidates honestly and keep the run evidence beside the small result.

The CSV example reduces an export to its header and the discount-refund pair behind a deliberately introduced accounting error. The JSON Lines example isolates one identifier that changes after a lossy numeric conversion. These are controlled fixtures, with three observations per candidate. Their posts explain which statements the successful reductions support and why an unresolved validity check can prevent a minimality claim.

The budget example stops after 12 predicate executions and keeps an incomplete checkpoint. A fresh run then reduces that checkpoint to one line, with its own baseline and final verification. The example bundle includes the generators and complete predicates; the released binary is the same one used for the recorded cases. This is the sort of documentation we want beside a small tool: examples that can be rerun and checked.