Replace hardcoded hex with Tiny Wire tokens in Performance + Simulation

[LinzLos]

Description

Replace hardcoded hex in src/screens/Performance.tsx (insight-banner icon) and src/screens/Simulation.tsx (leftover chart-blue + check icon + banner border) with Tiny Wire tokens. (Performance's throughput chart is already token-pure via LedgerChart.)

Why

Token-purity / design-system sync. #5B9BD5 in Simulation is a leftover of the old chart-blue that LedgerChart retired elsewhere.

Mapping

Hex	→ Token	File · Lines
#1b4079	--info	Performance 236, 237, 238
#afbcd0	--info-mid	Performance 228 · Simulation 203
#629460	--brand	Simulation 756
#5B9BD5	--chart-azure	Simulation 846

Recommended prerequisite

None.

Scope

UI-only, two files (disjoint from all other debt issues). No chart code change.

Touches

• src/screens/Performance.tsx
• src/screens/Simulation.tsx

Source

phase4-brief.md → Item 3.

Owner

Lindsay.

Acceptance criteria

• Listed hex replaced with tokens.
• npm run build clean; both screens unchanged in light + dark.