chore(roadmap): re-sync this repo's copy with the merged canonical

[abrcrmb]

What and why

AGENTS.md §12 and scripts/roadmap-merge both assume the five ROADMAP.md copies are identical apart
from a repo's own rows. After the Wave-format PRs merged they were not: each repo carried only its own
Changelog line and a stale W-05, while canonical had gained the org-side entries. This copies the merged
canonical back into this repo so the next merge has a real ancestor.

Changes

• ROADMAP.md replaced with the merged canonical (.github main as of docs(sdk): bring the README up to date with the shipped SDK and indexer #31) in repo-root link form, then
  §3 recomputed with scripts/roadmap-progress --write.
• One Changelog entry naming this repo's copy-back, added under the table header (newest first). The
  re-sync commit alone carried only lines copied in from canonical, which would have left this repo's
  history with no record that its copy was re-synced — the same silence that let the seven copies drift
  to 92 divergent statuses.
• No row ID, status, priority, dependency or Done when is authored here. Everything else in the diff
  came from the canonical file, and the rows this repo owns are unchanged.

Hard rules / invariants touched

None. §12 maintenance only.

Tests

Verified in this checkout before committing, not assumed:

• diff of this copy against canonical, with the ADR link form normalized: exactly 1 line, this PR's
  own Changelog entry. Everything else is byte-identical.
• W-05 reads DONE (propagated from the org row, which .github completed).
• The seven docs/wave-issue-format rows (M1-38…M1-41, M2-20, M2-21, M3-27) are present.
• Duplicate row-ID scan across the whole file: 0.
• scripts/roadmap-progress --write re-run over the file after adding the entry: 0 further changes,
  so §3 is stable at 211 rows / 75 DONE / 40%.

Docs / ADR

ROADMAP.md only. No ADR — no decision changes.

Roadmap

Changelog entry added: yes, one naming this repo's copy-back. Row statuses: none authored in this repo;
the propagated W-05 is an org row completed by .github. Last updated refreshed with canonical.

Assumptions and open questions

• Depends on .github docs: SDK API reference, matching current exports (M2-17) #28, docs: sync "verified payee" wording from Kinlock-Org/.github #30 and docs(sdk): bring the README up to date with the shipped SDK and indexer #31 being merged. docs: sync "verified payee" wording from Kinlock-Org/.github #30 replayed docs: point to the documentation-issue hub #29's Changelog union onto main
  after the stack stranded it; docs(sdk): bring the README up to date with the shipped SDK and indexer #31 anchored roadmap-merge's link normalization, without which copying
  canonical into this repo mangles a Changelog sentence. All three are merged, so the file copied here is
  final.
• The ADR link form is the only intentional difference from canonical besides this PR's own entry, and it
  is the difference sync-docs.sh and roadmap-merge already normalize on read.
• roadmap-check and docs-in-sync are the gates this repo's CI applies; both are satisfied by a
  ROADMAP.md diff carrying a Changelog entry, and no docs/* file is touched.
• After this merges, .github's canonical should union this entry on the next roadmap-merge run rather
  than report it as divergence — that is the established pattern for repo-side entries.