chore(codegen): drop committed src/blockchain/abi.ts in favor of generated src/generated.ts

The 58KB src/blockchain/abi.ts was the output of the legacy hardhat-based
wagmi config and was being committed verbatim. Since wagmi.config.ts now
emits src/generated.ts (gitignored, regenerated on every prestart via
`bun run wagmi:gen`), keeping the old artifact in the tree was just dead
weight.

- Remove src/blockchain/abi.ts from tracking
- Repoint 4 imports (sellerMethods, events, provider, BuyerSearchComponent)
  from `@/blockchain/abi` / `./abi` to `@/generated`
- contracts:compile now injects ALCHEMY_API_KEY=placeholder + a default
  test MNEMONIC so hardhat.config.ts can load without a manual .env in
  the submodule (matches the placeholder values used in p2pix-front-end's
  submodule .env)

package.json

@@ -13,7 +13,7 @@
     "lint:fix": "eslint . --fix",
     "format": "prettier --write \"src/**/*.{ts,vue,json}\"",
     "format:check": "prettier --check \"src/**/*.{ts,vue,json}\"",
-    "contracts:compile": "cd p2pix-smart-contracts && bun install && bunx hardhat compile",
+    "contracts:compile": "cd p2pix-smart-contracts && bun install && ALCHEMY_API_KEY=placeholder MNEMONIC='test test test test test test test test test test test junk' bunx hardhat compile",
     "prewagmi:gen": "bun run contracts:compile",
     "wagmi:gen": "bun ./node_modules/@wagmi/cli/dist/esm/cli.js generate"
   },