Add ElkSharp rendering architecture docs, ADRs, tutorial, AGENTS rules
Five documentation deliverables for the ElkSharp rendering improvements:
1. docs/workflow/engine/16-elksharp-rendering-architecture.md (453 lines)
Full pipeline: Sugiyama stages, edge routing strategies, hybrid
deterministic mode, gateway geometry, 18-category scoring system,
corridor routing, Y-gutter expansion, diagnostics.
2. docs/workflow/engine/17-elksharp-architectural-decisions.md (259 lines)
Six ADRs: short-stub normalization, gateway vertex entries, Y-gutter
expansion, corridor rerouting, FinalScore adjustment, alongside
detection.
3. docs/workflow/tutorials/10-rendering/README.md (234 lines)
Practical tutorial: setup, layout options, SVG/PNG rendering,
diagnostics capture, violation reports, full end-to-end example.
4. src/__Libraries/StellaOps.ElkSharp/AGENTS.md — 7 new local rules
for Y-gutter, corridor reroute, gateway vertices, FinalScore
adjustments, short-stub normalization, alongside detection,
target-join spread.
5. docs/workflow/ENGINE.md — replaced monolithic ElkSharp paragraph
with structured pipeline overview, effort-level table, and links
to the new architecture docs.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
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