Fix unscored reviews and sidebar favicon

[sgardoll]

Summary

• keep structured Code Review payloads without score fields in the intended Not scored state instead of coercing them to 0 / High risk
• add regression coverage for missing scores
• replace the cached favicon URL with an exact copy of the rendered sidebar icon dimensions, path, stroke, radius, and colors

Verification

• npm test (75 passed)
• npm run build
• git diff --check
• production HTML, JavaScript, and favicon hashes match the local build

[greptile-apps]

Greptile Summary

This PR preserves the unscored state of structured reviews that omit a score and updates the application favicon to match the sidebar branding.

• Treats null, undefined, empty, and whitespace-only score values as absent rather than coercing them to zero.
• Adds regression coverage for structured reviews without score fields.
• Replaces the previous favicon asset and updates the HTML reference to the versioned brand icon.

Confidence Score: 5/5

The PR appears safe to merge with no actionable defects identified.

The score normalization now preserves missing and blank values as unscored while continuing to accept zero, numeric strings, nested values, and legacy markdown scores, and the favicon reference resolves to the newly added asset.

Important Files Changed

Filename	Overview
src/reviewPresentation.js	Safely distinguishes absent or blank scores from valid numeric values while retaining legacy score parsing.
src/reviewPresentation.test.js	Adds focused regression coverage confirming that structured reviews without scores remain unscored.
index.html	Updates the favicon reference to the newly added versioned brand asset.
public/favicon-brand-v2.svg	Adds the replacement SVG favicon using the intended brand geometry, gradient, and icon styling.

_{Reviews (1): Last reviewed commit: "fix: match favicon to sidebar brand" | Re-trigger Greptile}