Summary

• add a focused repro test for issue #78 using the DISCH fixture with schMaxTraceDistance=6
• assert duplicate raw segments exist in solver traces (bug repro)
• add post-processing trace line dedupe per globalConnNetId + segment

Verification

• bun test tests/solvers/SchematicTracePipelineSolver/SchematicTracePipelineSolver_repro78.test.ts
• bun test

Closes #78 /claim #78