feat: apply fanout boundary padding

[seveibar]

Summary

• carry fanoutBoundaryPadding through routing phase plans and local autorouter strategy context
• use <autoroutingphase> padding in preference to containing <breakout> padding
• resolve the fanout solver's sharedBoundary from the union of source pad obstacles only
• support scalar and directional padding, rotated pads, and multiple source footprints
• preserve the solver's existing automatic pitch-based boundary inference when the prop is omitted
• update PCB and multi-stage autorouting snapshots for the BGA-plus-decoupling-caps and directed fanout cases

Behavior

padding continues to control breakout layout bounds. fanoutBoundaryPadding controls where fanout prefixes terminate. Nearby destination parts and component keepouts do not enlarge the fanout boundary; the downstream autorouter continues from that boundary to the destinations.

When a phase supplies fanoutBoundaryPadding, it overrides the containing breakout value for that phase.

Dependency

This uses @tscircuit/props@^0.0.598. tscircuit/props#764 is merged, 0.0.598 is published, and the installed npm artifact exports the FanoutBoundaryPadding type, schema, and component props.

Validation

• bun test — 1,277 passed, 31 skipped, 0 failed
• bunx tsc --noEmit
• bun run build
• targeted fanout, single-layer fanout, BGA breakout, strategy, preset, and shared-boundary tests
• visually inspected the updated BGA breakout PNG; fanout prefixes end around the BGA and downstream routes continue to the four capacitors
• git diff --check

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Actions	Updated (UTC)
tscircuit-core-benchmarks	Ready	Preview, Comment	Jul 28, 2026 7:51pm