refactor-break-bw-compatlisted

# Breaking Refactors — Scorched Earth Backward compatibility is the tax the present pays to the past. This skill stops paying. Every compat shim, every legacy adapter, every "v1 still supported" branch is debt that compounds against the reader. Tear it all out. Break everything. Rebuild the system as if the old shape never existed. There is no migration plan. There is no deprecation window. There is the old shape, and there is the right shape, and the only acceptable end state is the right shape with zero residue of the old. ## Doctrine 1. **Break first, apologize never.** Do not ask whether a thing can be broken. Assume it must be. The default verdict is demolition. 2. **One shape, no adapters.** The new design owns the entire surface. Never write new-to-old bridges, fallbacks, or translation layers — they resurrect the corpse you came to bury. 3. **Total migration or nothing.** A half-migrated codebase is the only true failure state. If you touch a subsystem, every caller leaves on the new API before you stop. 4. **Callers are not sacred.** "Unknown external consumers" is not a reason to preserve — it is a reason to rewrite their contract and let them adapt. You change the interface; the world changes with it. 5. **Delete, never disable.** Flags, gates, version checks, `if legacy:` — collapse to the winning branch and erase the fork entirely. Version control is the only museum. 6. **Old tests are old assumptions.** Tests that assert the legacy behavior encode the contra