Fix AssetBadge colour hashing and AssetPill export

[xxCodexIAxx]

Summary

Fixes the AssetBadge consistency issues from #90.

• Replaces the 5-entry static asset colour map with a deterministic hash-to-palette picker using 10 colour pairs.
• Keeps colours stable for the same asset code without making every unknown asset fall back to the same grey badge.
• Centers short icon labels with a fixed-width inner span and uppercases the displayed 1-2 character symbol.
• Exports AssetBadge and AssetPill from src/components/index.ts so package consumers can import AssetPill from sorokit-ui.

Validation

• Reviewed the component changes against the acceptance criteria.
• Did not run npm run build locally in this environment; the PR is limited to deterministic TypeScript/JSX component and barrel export changes.

Bounty

Fixes #90

Payout wallet: 0x776CbBb63D81c08B4090DB503eAE7FDb8fBd7c6f