task: Make sure every end-user project listed in the docs is also on celo.org/ecosystem

[GigaHierz]

Part of #2266.

What needs to be done?

The docs list end-user projects that belong on the ecosystem site as well. At bdf40b37:

• home/wallets.mdx — 13 wallet entries
• home/exchanges.mdx — 7 exchanges (Binance, Coinbase, Uniswap, Velodrome, Ubeswap, Mento, plus a CoinMarketCap link)
• home/ramps.mdx — 20 ramp providers (Banxa … Yellow Card)

Decided: the docs stay the developer-facing source, and end-user discovery of these projects belongs on https://celo.org/ecosystem (verified 200). Long-term the docs should be able to point there instead of maintaining vendor lists.

Definition of done

• Sheet: every project from the three pages × present on celo.org/ecosystem yes/no (link in this issue)
• Ops (outside this repo): missing projects submitted to the ecosystem-site owner through their intake process
• Once listed, home/wallets, home/exchanges, home/ramps (or their Learn successors after story: Learn tab — move home/* (plus kept L1 content) to learn/* #2258) link to the ecosystem page as the canonical end-user directory
• Decision recorded (OPEN): keep the vendor lists in the docs as well, or reduce them to "see the ecosystem page" once parity is confirmed

Non-goals

Splitting end-user vs developer wallet pages (#2256); moving pages (#2258).

Depends on / blocks

No dependencies — can start now. #2258 must not delete these pages before this lands.

Measured at: bdf40b37