Price CATs that trade on Forge when Dexie has no price for them

[awizardxch]

Problem

Sage prices CATs from Dexie's v3/prices/tickers, which Dexie builds from offers completed on Dexie. A token that trades only through Forge's AMM pools never appears in that list, so Sage shows it with no value however actively it trades. On testnet today Dexie's list holds 4 tokens.

Change

Forge serves its own ticker list in Dexie's exact shape at /api/v1/prices/tickers:

• One ticker per CAT that sits in an XCH pool. last_price is XCH per whole token, the mid price of the token's deepest XCH pool, with weighted pools priced by their weights.
• A pool below a depth floor never prices anything: 1 XCH on mainnet, 0.01 TXCH on testnet. A near-empty pool can be pushed to any price for a few mojos, and a wallet would show that as a balance's value.
• Extra fields say where a price came from: source: "forge", pool_id, depth_xch, state_as_of. The endpoint is public, read-only and answers any origin.

PriceContext fetches Dexie and Forge in parallel with Promise.allSettled:

• Dexie stays primary. Forge only fills a token Dexie has no last_price (or ask) for.
• Either source failing leaves the other in place. Before this change a Dexie outage cleared every CAT price.
• forgeApiUrl(path, isTestnet) is added to src/lib/urls.ts beside the Dexie and MintGarden helpers.

Merge behavior, checked in a browser engine:

Case	Result
Both up	Dexie's price where it has one; Forge fills tokens Dexie has no last price for
Dexie down	Forge prices its tokens
Forge down	Identical to today

tsc -p tsconfig.app.json, eslint and prettier pass on the touched files.

Draft until the Forge endpoint is live on both networks. The hosts are Forge's routers (forge-ui-production.up.railway.app for mainnet, forge-responder.up.railway.app for testnet), kept in one function so a custom domain is a one-line change.

🤖 Generated with Claude Code

[awizardxch]

Closing for now: we need to settle the hosting for a price feed (caching, stable domain) before proposing it. Will reopen or replace it when that's in place.