Add EIDEX to centralized swap listing

[slaenov]

Adds EIDEX to the centralized swap platform listing.

EIDEX is a non-custodial route screener for cross-chain swaps: it queries live quotes from 33+ sources - DEX aggregators, bridges and no-KYC instant exchangers - and ranks them by how much the user actually receives. It never holds funds and
never executes the swap; the exchange happens directly with the provider you pick. No account is needed.

ZEC is supported natively, and the comparison covers several exchangers already listed on this page, including ChangeNOW, StealthEX and LetsExchange - so a ZEC holder can see who gives the best output before committing.

Quotes are indicative, not executable - final terms are set by the provider. EIDEX charges no commission and adds no markup; providers pay a referral reward when a user proceeds to swap, which is stated on the page itself and does not affect the ranking (routes are ordered strictly by output).

Logo added as PNG at 1040x432 with a transparent background, matching the format of the existing entries.

To verify: open https://eidex.io/screener/zec-zec-to-btc-btc, pick ZEC -> BTC, enter an amount and press "Build route".

[slaenov]

Hi! The three workflows on this PR (Playwright Tests, Unit tests, Egress check) are sitting in "action_required" - they need a maintainer to approve the run, since this is my first PR in this repo. Could someone trigger them? Happy to address anything they surface.