fix: replace placeholder donation addresses with the real wallets

The addresses in the donation block were never real. The Bitcoin one fails its
bech32 checksum and Blockstream rejects it outright; the Ethereum one fails
EIP-55 and belongs to an address with no history, so any wallet that lowercased
it before sending would have delivered real money to nobody; the Solana string
is not even base58 - its tail is the QWERTY top row typed backwards.

Verified before use: BTC bech32 valid and accepted by Blockstream, ETH EIP-55
exact with 16 outgoing transactions on-chain, SOL 32 bytes owned by the System
Program with a live balance.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

README.md

@@ -312,9 +312,9 @@ Date: 2026-04-30
 
 If you find this project useful, consider supporting its continued development:
 
-**Bitcoin (BTC)**: `bc1ql5klyv78t0a5g59y3tczv8ejy9l740x3zg0cge`  
-**Ethereum (ETH)**: `0x3f707d3543A6C301B3Bf47eBc4B469e017a119B4`  
-**Solana (SOL)**: `G7iZQ3iQ7k5t9E9g8Y7u6i5t4r3e2w1q0P9O8I7U6Y5`
+**Bitcoin (BTC)**: `bc1q3zlkpu95amtcltsk85y0eacyzzk29v68tgc5hx`  
+**Ethereum (ETH)**: `0x76C00887C250c08f4E063638e0aF2ac745Fcc0D1`  
+**Solana (SOL)**: `2o6bKUHyMuHqUoR3RwaMrQW6ZaDy9CwUKkejFSMKeFv2`
 
 ---