v0.4.3 — set-validated tier made real + roadmap doc

The top of the verification ladder, made real

flows v2 begins. The set-validated tier shipped as a seam in v0.4.0 (ADR-007: set-equality is non-vendorable, so it lives in user space) — but nothing demonstrated it. Now repolore dogfoods it:

• Reference extractor — .repolore/validators/update-classification-seteq.mjs (plain Node stdlib, ~70 lines) rebuilds update.mjs's disposition set from code: every report.<key>.push call site, mapped to the flow step it folds into, emitted as the {steps, edges, branches} JSON the contract specifies.
• flows/update-classification reaches set-validated — the page flips flow_asserts_complete: true, so a new disposition added to update.mjs that nobody writes into the flow is now a hard fail: the omitted-branch catch no lower tier can do.
• Copyable worked example — references/flow.md documents the extractor as the starting shape for your own closed-world tool flows (open-world request/async flows honestly stay at branch-audited).
• 5 new tests pin the chain: exact set reconstruction, the new-disposition catch, the live page at the top tier, hard-fail with asserts_complete, graceful degrade without it.

A readable roadmap

The README's roadmap had grown into a 20-entry wall of prose. It now lives in docs/ROADMAP.md: Now (flows v2, extractor ticked) / Next (v0.5+) / tooling debt / version history, newest first. The README keeps a pointer.