docs(roadmap): propose an MTIP export as an optional layout augment to a SysML v1 migration

[devin-ai-integration]

What and why

A Cameo/MagicDraw .mdzip migrated through sysml -convert sysml carries which elements each diagram shows (#524 writes them as view usages) but not where the diagram draws them — the tool keeps diagram geometry outside the XMI. Open-MBEE's MTIP plugin (mtip-cameo) reads that geometry through the tool's API and writes it into its HUDS XML (per-diagram bounds, connector breakpoints, colors, fonts, images, keyed by element id).

This adds a fourth item under Proposed in docs/project/roadmap.md: read an MTIP export as an optional augment (-layout <mtip-export.xml>), not as a second input format. The .mdzip/.xmi stays the one source of structure and behavior; the HUDS file contributes presentation only, joined to the migrated views by element id and written as the landed DiagramLayout metadata (metadata Layout about …, metadata Route about …, @Canvas) in the view usage's body — standard metadata, not a sidecar. The item states what is refused or reported (unmatched ids, skipped diagrams, malformed records, an export from a different project; colors/fonts/images that DiagramLayout has no attribute for), that output without -layout is byte-identical to today's, that fixtures come from MTIP's own test exports plus a hand-written pair, and that the gate is an MTIP export of a model whose .mdzip is also available — none exists yet, so the item is not started. The "What remains open" Proposed bullet is threaded accordingly.

Roadmap-only; no code, no changelog fragment (as with earlier roadmap-only edits).

How it was verified

• python3 scripts/check-doc-links.py — 0 broken links
• python3 scripts/check-doc-ids.py — no internal work-item labels
• python3 -m mkdocs build --strict — passes

Checklist

• make test and make lint pass locally (docs-only change; the documentation gates above are the relevant ones)
• Tests added or updated for the change (n/a — roadmap text)
• Documentation extended where it already covers the surface (see CONTRIBUTING.md)
• Changelog entry added as changes/unreleased/<slug>.<section>.md, not as an edit to CHANGELOG.md (n/a — roadmap-only edits carry none)
• baselines regenerated and make docs-counts run if a gate count moved (no count moved)
• No internal work-item labels (waves, slices, F4, K5) in the body, docs, or changelog

[devin-ai-integration]

I'll fix CI failures and address comments from users with write access. I'll skip comments containing "(aside)".

• Disable automatic comment, CI, and merge conflict monitoring

[devin-ai-integration]

✅ Devin Review: No Issues Found

Devin Review analyzed this PR and found no bugs or issues to report.