The short-stub fallback in NormalizeExitPath fixes 2 entry-angle violations
(edge/7, edge/27) that persisted because the default long-stub normalization
created horizontal segments crossing nodes in occupied Y-bands. When the long
stub fails HasClearSourceExitSegment, the normalizer now tries a 24px short
stub that creates a perpendicular dog-leg exit avoiding the blocking node.
Also adds boundary-first routing infrastructure (not yet active in the main
path) including global boundary slot pre-computation, A* routing with
pre-assigned slots, coordinated cluster repair with net-total promotion
criterion, and gateway target approach overshoot clipping. The net-total
criterion (CountTotalHardViolations) is proven to reduce violations from
10 to 7 but requires expensive BuildFinalRestabilizedCandidate calls that
exceed the 15s speed budget.
Root cause analysis confirms the remaining 8 violations (3 gateway hooks,
1 target join, 1 shared lane, 3 under-node) are caused by Sugiyama node
placement creating routing corridors too narrow for clean edge routing.
The fix must happen upstream in node placement, not edge post-processing.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
