Summary

Adds test for converting Smoothieboard DSN file to Circuit JSON.

Test Coverage

• Parses the smoothieboard-repro.dsn file (complex multi-layer PCB)
• Verifies DSN structure: resolution, units, layers, boundary
• Converts to Circuit JSON with 3000+ elements
• Checks for NaN/undefined values in output

Results

=== DSN Structure Analysis ===
Resolution: 1 um
Images (footprints): 119
Padstacks: 136
Placement components: 274
Network nets: 314
Wiring wires: 0

=== Circuit JSON Analysis ===
pcb_board: 1
pcb_component: 405
pcb_smtpad: 2907
pcb_port: 2922
source_port: 2922
source_component: 405

/claim #54