fix: prevent hash overflow to NaN in getColorFromString (#651)

[thairc-dev]

Fixes #651

Cause

When passing long strings (e.g. "n".repeat(300)), accumulating acc * 31 + charCodeAt(0) overflows JavaScript's Number.MAX_VALUE to Infinity. Subsequently, Infinity % 360 evaluates to NaN, returning an invalid color string hsl(NaN, 100%, 50%, 1).

Solution

• Use 32-bit integer bitwise OR (| 0) on each hash accumulation step to keep the hash bounded within signed 32-bit integer range.
• Use Math.abs(hash) % 360 to guarantee a valid non-negative hue integer between 0 and 359.

Verification

Added tests/getColorFromString.test.ts verifying valid HSL format, alpha parameter handling, and long string handling ("n".repeat(300)). All tests pass cleanly.

[vercel]

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Project	Deployment	Actions	Updated (UTC)
schematic-trace-solver	Ready	Preview, Comment	Jul 22, 2026 10:21am

[thairc-dev]

Unit test tests/get-color-from-string.test.ts passes 100% (3/3). Biome format check, type check, and Vercel preview deployment are all green. Ready for review!