`ROADMAP.md`: "Open trackers" section is stale — referenced issues are closed

[TexasCoding]

Housekeeping.

Stale references in ROADMAP.md:45-56

• #45 — listed as open; closed 2026-05-19. The json={} workaround was verified.
• #53 — listed as open; closed 2026-05-19. Nested $ref drift check no longer applicable (current spec has no nested refs to chase).
• #106 — listed as a tracking issue; it's PR #106 (a merge), not an issue. The Wave 5 polish items it grouped were filed as separate issues that have either landed or are being filed under this batch.

Fix

1. Delete the "Open trackers" section, or repoint it at the live issues filed in this batch (whichever set is still open at merge time).
2. Refresh the "Next milestone" section — it lists carry-overs this batch now files explicitly. After the batch lands, "Next milestone" should either name a real scoped milestone or be removed in favor of "Pick from gh issue list".
3. Keep the "Shipped" and "Execution conventions" sections — those stay accurate.

Acceptance

• ROADMAP.md references no closed issues.
• No commit-time test exists for this; manual review at merge.