fix: parse scientific notation in pcb coordinate strings

[asapsav]

Summary

Footprint primitives with CAD-imported coordinates in scientific notation (e.g. pcbX="-1.1368683772161603e-13mm") were failing with:

source_invalid_component_property_error: Invalid pcbY value for SmtPad:
Invalid calc() expression. expression="1.1368683772161603e-13mm"

This happens when footprints are auto-imported from EasyEDA/JLC/KiCad sources that serialize near-zero values as IEEE float dust.

Root cause: In evaluateCalcString.ts, tokenize() only consumed digits and . for numbers. For 1.1368683772161603e-13mm it parsed 1.1368683772161603, stopped at e, and treated e as a unit suffix → Unknown unit: "e", which upstream is reported as an invalid calc expression.

Changes

• Extend the number lexer in tokenize() to accept optional scientific notation (e/E, optional sign, exponent digits) before the optional unit suffix (mm, etc.)
• Normalize -0 to 0 in the final result (avoids negative zero from unary - on dust values)

Testing

Unit tests (evaluateCalcString):

• 1.5e-2mm → 0.015
• 2E+3mm → 2000
• calc(1e-13mm + 2mm) → 2

Integration test (<smtpad>):

• Footprint with pcbX="-1.1368683772161603e-13mm" and pcbY="0mm" renders without source_invalid_component_property_error; pad x is ~0

Regression checks:

• Existing calc expression tests pass (calc(board.minX + 1mm), legacy board.minx, etc.)
• RP2040 decoupling capacitors repro passes (uses the same scientific-notation coordinate in the RP2040 footprint fixture)

to reproduce error with and without the fix:

git checkout 3477027 -- lib/utils/evaluateCalcString.ts
bun test tests/utils/evaluate-calc-string.test.ts tests/components/primitive-components/smtpad-scientific-notation-coordinates.test.tsx
git checkout HEAD -- lib/utils/evaluateCalcString.ts # restore fix

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Project	Deployment	Actions	Updated (UTC)
tscircuit-core-benchmarks	Ready	Preview, Comment	May 25, 2026 9:01am

[imrishabh18]

I am not sure if this is the right place for the fix, can you create a test in here to demonstrate the fix

[seveibar]

needs a test

[asapsav]

added tests back

to reproduce error with and without the fix:

git checkout 34770277 -- lib/utils/evaluateCalcString.ts
bun test tests/utils/evaluate-calc-string.test.ts tests/components/primitive-components/smtpad-scientific-notation-coordinates.test.tsx
git checkout HEAD -- lib/utils/evaluateCalcString.ts   # restore fix

@imrishabh18 where is the right place to fix? new to the repo