fix(isRgbColor): accept alpha values with more than 2 decimal digits

[JSap0914]

Summary

isRgbColor incorrectly rejected valid CSS rgba() colors where the alpha value had more than 2 decimal digits, or where alpha was 1.00 (trailing zeros on the boundary value 1).

Closes #2792

Bug

The old alpha sub-pattern (0?\.\d\d?|1(\.0)?|0(\.0)?) limited the decimal part to at most 2 digits and only allowed exactly one trailing zero on the boundary values:

isRgbColor('rgba(255,255,255,.123)') // false — wrong, should be true
isRgbColor('rgba(255,255,255,1.00)') // false — wrong, should be true
isRgbColor('rgba(0,0,0,0.123)')      // false — wrong, should be true
isRgbColor('rgba(5%,5%,5%,.321)')    // false — wrong, should be true

The CSS specification defines <alpha-value> as a CSS <number>, which imposes no limit on decimal precision.

Fix

Changed the alpha sub-pattern in both rgbaColor and rgbaColorPercent from:

(0?\.\d\d?|1(\.0)?|0(\.0)?)

to:

(0?\.\d+|1(\.0+)?|0(\.0+)?)

This allows any number of decimal digits after the dot and properly handles trailing zeros on the opaque (1) and transparent (0) boundary values.

Verification

• Before fix (RED): npm test → 317 passing, 1 failing (validator.isRgbColor("rgba(255,255,255,.123)") failed but should have passed)
• After fix (GREEN): npm test → 318 passing

All existing tests continue to pass. Values outside the 0–1 range (rgba(0,0,0,2), rgba(0,0,0,1.5)) are still correctly rejected.

[Copilot]

Copilot was unable to review this pull request because the user who requested the review has reached their quota limit.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (a38f15b) to head (f46b338).

Additional details and impacted files

@@            Coverage Diff            @@
##            master     #2793   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files          114       114           
  Lines         2587      2587           
  Branches       656       656           
=========================================
  Hits          2587      2587           

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.