docs(design-system): migrate asset URLs to arcadians.dev [GRO-449]

[teallarson]

Linear ticket: GRO-449

Summary

Moves Arcade toolkit icon references from design-system.arcade.dev to design-system.arcadians.dev across the docs generator, checked-in toolkit data, fixtures, and consumer expectations.

• New fallback metadata uses the new asset host.
• The metadata-freshness heuristic recognizes the new fallback URL.
• Checked-in toolkit snapshots and tests no longer publish or expect the old host.

Companion runtime/config change: ArcadeAI/monorepo#4841.

Test plan

• pnpm lint
• pnpm typecheck
• pnpm test — 70 files, 876 tests passed
• pnpm build — 295 pages generated
• Representative icon URLs on the new host return HTTP 200 and are byte-identical to the old host
• Repository search confirms no migrated old-host references remain

The checks ran under Node 25.9.0; the repository declares Node 22.x, so pnpm emitted an engine warning. No DNS, storage, deployment, or hosting settings were changed.

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Project	Deployment	Actions	Updated
docs	Ready	Preview	Oct 1, 2026 4:36pm UTC