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)

src/blockchain/events.ts

@@ -3,7 +3,7 @@ import { formatEther, toHex, stringToHex } from 'viem';
 import type { PublicClient, Address } from 'viem';
 import { Networks } from '@/config/networks';
 import { getContract } from './provider';
-import { p2PixAbi } from './abi';
+import { p2PixAbi } from '@/generated';
 import type { ValidDeposit } from '@/model/ValidDeposit';
 import type { NetworkConfig } from '@/model/NetworkEnum';
 import type { UnreleasedLock } from '@/model/UnreleasedLock';

src/blockchain/provider.ts

@@ -1,4 +1,4 @@
-import { p2PixAbi } from './abi';
+import { p2PixAbi } from '@/generated';
 import { updateWalletStatus } from './wallet';
 import {
   createPublicClient,

src/blockchain/sellerMethods.ts

@@ -1,6 +1,6 @@
 import { getContract, getPublicClient, getWalletClient } from './provider';
 import { parseEther, toHex, ChainContract } from 'viem';
-import { mockTokenAbi } from './abi';
+import { mockTokenAbi } from '@/generated';
 import { useUser } from '@/composables/useUser';
 import { createParticipant } from '@/utils/bbPay';
 import type { Participant } from '@/utils/bbPay';

src/components/BuyerSteps/BuyerSearchComponent.vue

@@ -12,7 +12,7 @@ import { onClickOutside } from '@vueuse/core';
 import { Networks } from '@/config/networks';
 import { TokenEnum } from '@/model/NetworkEnum';
 import { getContract } from '@/blockchain/provider';
-import { reputationAbi } from '@/blockchain/abi';
+import { reputationAbi } from '@/generated';
 import { type Address } from 'viem';
 
 // Store reference