Show swap token logos from the token contracts on NEAR

[n13]

Why

1Click's /v0/tokens has no image field (verified against the live API and its OpenAPI spec), and the Defuse console API is the same list. The logos live on NEAR itself: every listed token is, or has a sibling that is, a NEAR token contract whose metadata carries an icon.

What was tested with curl / RPC before writing code

• ft_metadata on NEP-141 contracts (nep141:…): returns icon as a data URI: SVG (USDC, ETH, FRAX, AURORA, mpDAO, ZEC…), PNG (JAMBO, CFI), JPEG (BLACKDRAGON), WebP (SHITZU). Some have none (wrap.near, qtc.omft.near, WBTC, HAPI…).
• mt_metadata_base_by_token_id on the NEP-245 HOT bridge contract (nep245:v2_1.omni.hot.tg:<token_id>, 36 listings, one batched call): returns icon as an https URL (storage.herewallet.app, coin-images.coingecko.com, bscscan). Every URL downloads with HTTP 200 and an image content type. Three carry the literal string todo.
• 1cs_v1:… listings (25) are chain-native ids with no NEAR contract.
• Every image the app's top-20 list would show was downloaded for inspection to ~/play/quantus-network/.agent-tmp/claude/token-icons/.

What changed

• SDK NearRpcService: read-only view calls over JSON-RPC against https://free.rpc.fastnear.com (AppConstants.nearRpcEndpoint).
• SDK SwapTokenIconService: iconFor(token) reads the metadata icon (NEP-141 or NEP-245 by asset id), decodes a data URI or downloads an https URL, and returns SwapTokenIcon(bytes, mimeType). Each listing is fetched once; a failed fetch is forgotten so it is retried next time; a junk icon value is logged and treated as none.
• SwapToken.iconAssetId: the listing whose metadata carries the symbol's logo. The token's own asset when it has a NEAR contract, else the first listing of the same symbol that has one (so ZEC on Solana would still get Zcash's logo), else null.
• Native chain first: a listing whose chain is the coin's own (symbol equals chain, or W + chain) now beats the main-network order. Before, ZEC resolved to the Solana SPL wrapper and wNEAR to a Solana wrapper, neither with a NEAR contract, and arguably not the asset a user means.
• TokenIcon watches swapTokenIconProvider(token) and renders SvgPicture.memory or Image.memory with the monogram as fallback (loading, none, decode error). The network badge stays a monogram.

Tests

• SDK: NEP-141 data URI → bytes; NEP-245 token id in the call and the URL downloaded with its content type; sibling listing supplies the logo; no logo without a NEAR listing, with a null icon, or with a junk icon; one fetch per listing and a failed fetch retried. Swap service: own chain wins (ZEC, wNEAR), iconAssetId for own, sibling and none.
• App: monogram without a logo, SVG logo, raster logo. Swap flow tests pass.

[n13]

Reviewer model: GPT-6.1 Sol

Verdict (advisory): Approve

Reviewed d06992576d13911b377b0b02cafe0b8555447d9b against base e7de1a708bcf6a72d6e530170294720b7ca89602. No blocking findings.

The metadata lookup, data URI/HTTPS image handling, shared per-listing cache, failure eviction, and monogram fallback are consistent with the intended behavior. I also traced the native-chain preference through listing selection, quote asset IDs, deposit deadlines, and network-specific address handling.

Validation:

• SDK: flutter test --no-pub --reporter=expanded test/services/swap_service_test.dart test/services/swap_token_icon_service_test.dart — 46 passed.
• Mobile: flutter test --no-pub --reporter=expanded test/unit/token_icon_test.dart test/screens/swap_flow_test.dart test/unit/swap_math_test.dart — 30 passed. Both test commands ran through repository-pinned Melos from the worktree root.
• Formatting check on all 11 changed Dart files and git diff --check — passed without changing source.
• Read-only live checks: fetched the current 1Click listing and top-20 NEP-141 metadata, covering SVG, PNG, JPEG, WebP, and absent icons; verified a NEP-245 metadata call and its HTTPS image response. The JSON-RPC request/byte decoding agrees with NEAR's contract-call documentation.

Validation limits: melos run analyze was stopped at the mandatory 10-second cap after the unaffected cold-wallet and miner packages passed; SDK/mobile analysis did not complete. The affected files compiled in the passing focused tests. GitHub currently reports three successful dependency-cooldown checks; those are separate from local test validation.