fix: add missing Unichain and Robinhood assets

[sethhrbek]

Summary

Cold loads now have checked-in logo URLs for Robinhood USDG/WETH and Unichain WETH instead of deterministic asset paths that return 404. Robinhood also gains the network metadata and artwork needed to complete the previously missing asset tree.

Fixes CONS-2628, CONS-2632.

Test plan

• Confirmed Robinhood's canonical USDG and WETH addresses against the official chain documentation
• Queried both Robinhood contracts over the public RPC to verify token names, symbols, and decimals
• Verified all metadata fields with jq and all logos as valid PNGs at the expected dimensions
• Verified the Unichain and Robinhood WETH logos are byte-identical to the existing Base WETH artwork
• Ran git diff --check
• Verified all four branch-hosted logo URLs return HTTP 200
• Ran make check; it remains nonzero with 368 repository-wide validation errors, compared with 366 on this branch before the Robinhood additions. The only two new errors are missing descriptive fields on the minimal Robinhood token metadata, matching the existing Unichain/Soneium token shape; the network metadata and PNG checks pass.

Post-Deploy Monitoring & Validation

• Owner/window: PR author, immediately after merge and for the first 15 minutes
• Check the raw master URLs for Robinhood network, USDG, and WETH logos plus Unichain WETH; healthy is HTTP 200 with Content-Type: image/png
• Cold-load Robinhood USDG/WETH and Unichain WETH with cache disabled; healthy is a logo on both the selected swap token and picker row without a failed image request
• There is no application log or dashboard for static asset delivery; use the browser network panel and direct URL status as the signal
• Any 404, non-PNG response, or broken cold-load logo is a failure signal; correct or revert the affected asset path before considering validation complete

[linear-code]

CONS-2628

CONS-2632