Design: several components use the green/red exception colors without the required aria-label, or colors outside the exception entirely

[Jaydbrown]

CONTRIBUTING.md's Design System section permits text-green-600/text-red-600 "only when accompanied by an aria-label so colour is never the sole signal." Several places use these (or other) hue colors without meeting that bar:

• components/stream/StreamCard.tsx:53 — rate amount uses text-green-600 dark:text-green-400 with no aria-label.
• components/stream/BatchStreamCreator.tsx:90 — rate display uses text-green-600 dark:text-green-400 font-bold with no aria-label.
• components/stream/BulkWithdrawButton.tsx:167 — progress fill uses bg-green-500, which isn't even covered by the exception (the exception is text-green-600 only, not bg-green-*).
• components/stream/BulkWithdrawButton.tsx:158 — excluded-streams notice uses text-amber-600 dark:text-amber-400, not in the exception list at all.
• components/ui/Input.tsx:22 — error state uses border-red-400 focus:border-red-500 focus:ring-red-500/10; border-red isn't covered by the text-only exception.
• app/settings/page.tsx:66 — "Settings saved" indicator uses text-green-600 dark:text-green-400 with no aria-label; line 167's reset button uses border-red-300 ... text-red-600 with no aria-label.
• app/stream/[id]/page.tsx:165 — "Stream is paused — balance frozen" text uses text-amber-600, not in the exception list.

None of these are catastrophic individually, but collectively they show CONTRIBUTING.md's own PR checklist item ("No hue-named colour classes without an aria-label") isn't being consistently enforced at review time. Worth a sweep to either add the required aria-labels or replace with black/white/gray per the documented rule.