docs: USAGE.adoc, catalogue.adoc and man/pons.1 document subcommands and flags the binary does not have

[hyperpolymath]

Problem

Three documents that landed in #39 describe a CLI that does not exist:

• docs/USAGE.adoc
• docs/catalogue.adoc
• docs/man/pons.1

They document these subcommands: extract, trace, spell, search, doctor, challenge and catalogue. They also document these flags: --rule, --lang, --protocol and --no-speculative, among others. The binary at main (7ec7e08) has only this surface:

pons scan <PATH> [--format human|json|sarif] [--fail-on info|warn|error]

catalogue.adoc says it is generated by pons catalogue. No such generator exists; it is scheduled for M7.

For a tool whose contract is "never dress a heuristic up as a proof", documentation that claims features the binary lacks is a correctness defect, not just stale text.

Acceptance criteria

• Every subcommand and flag in USAGE.adoc and man/pons.1 either exists in pons --help at the commit that closes this issue, or is marked planned (M) with its PLAN.adoc milestone.
• catalogue.adoc does not claim to be generated until the M7 generator and its drift test exist. Until then it lists only the 8 registered T0 rules, in RuleRegistry::all() order.
• A test or just recipe diffs the documented flag set against pons scan --help. A mutant that adds a fake flag to USAGE.adoc must turn it red.
• PROOF-PROGRESS.adoc "Known gaps" row is removed or updated when this closes.

Not a blocker for M4. It must close before the v0.1.0 tag (M8).