feat: add Binance WebSocket price provider

[louise-poole]

Summary

• Add BinanceWsProvider that subscribes to Binance bookTicker WebSocket streams for real-time bid/ask prices
• Pair discovery cross-references SharedMarketData tokens with Binance /api/v3/exchangeInfo, re-syncs every 60s
• Price resolution: direct pair (bid) → reverse pair (1/ask) → intermediate routing through USDT/USDC/ETH/BTC, using ask prices on the buy-side leg
• Reconnects with exponential backoff (5s → 60s max)
• Register as second default provider alongside Hyperliquid

[tamaralipows]

Thank you for taking this @louise-poole ! Just a few comments to make this easier if we ever need to debug in the future - again we can take it from here though 🙏

[dianacarvalho1]

Thank you @louise-poole ! Only have smol comments

[dianacarvalho1]

is there a reason why we shouldn't route through intermediate assets in Hyperliquid too?

[tamaralipows]

IIUC, we don't need to. Hyperliquid's oracle prices are all USD-denominated. So pricing any pair is just usd_price_in / usd_price_out. USD is the intermediate for every single pair. (Note each asset returns a single oraclePx value - not a pair price)

Binance is different: it has specific trading pairs (ETHUSDT, LINKBTC, etc.), so if there's no direct LINK/ETH pair, you have to explicitly route through USDT or BTC.

Let me know if I missed something though

[tamaralipows]

I rebased but it should still be fine to see the latest commits since they're signed with my name instead of Louise's

[Troshchk]

Thank you!
Looks good, have only one question

Approved by mistake

[dianacarvalho1]

Thank you @tamaralipows ! I see that the USDC like tokens are way more relevant here than in Hyperliquid!

[github-actions]

Breaking API Changes (Intentional)

Breaking API changes detected and declared in the PR title.
Ensure the minor version is bumped before merging (breaking changes on 0.x.x bump the minor).

semver-checks output

Checking fynd-core v0.43.2 -> v0.43.2 (no change; assume minor)
     Checked [   0.520s] 196 checks: 195 pass, 1 fail, 0 warn, 49 skip

--- failure function_missing: pub fn removed or renamed ---

Description:
A publicly-visible function cannot be imported by its prior path. A `pub use` may have been removed, or the function itself may have been renamed or removed entirely.
        ref: https://doc.rust-lang.org/cargo/reference/semver.html#item-remove
       impl: https://github.com/obi1kenobi/cargo-semver-checks/tree/v0.46.0/src/lints/function_missing.ron

Failed in:
  function fynd_core::price_guard::utils::resolve_token, previously in file fynd-core/src/price_guard/utils.rs:16

     Summary semver requires new major version: 1 major and 0 minor checks failed
    Finished [   0.776s] fynd-core
    Checking fynd-rpc v0.43.2 -> v0.43.2 (no change; assume minor)
     Checked [   0.083s] 196 checks: 196 pass, 49 skip
     Summary no semver update required
    Finished [   0.138s] fynd-rpc
    Checking fynd-rpc-types v0.43.2 -> v0.43.2 (no change; assume minor)
     Checked [   0.129s] 196 checks: 196 pass, 49 skip
     Summary no semver update required
    Finished [   0.209s] fynd-rpc-types
    Checking fynd-client v0.43.2 -> v0.43.2 (no change; assume minor)
     Checked [   0.142s] 196 checks: 196 pass, 49 skip
     Summary no semver update required
    Finished [   0.261s] fynd-client

[Troshchk]

Thank you @dianacarvalho1!
Looks good, have one question about the websocket reconnects

[propellerci]

This PR is included in version 0.44.0 🎉