Add Playwright E2E tests

[AugustoL]

Add comprehensive Playwright E2E test suite for OpenScan Explorer using Ethereum mainnet data.

Test Coverage (43 tests)

Block Page (7 tests)

• Pre-London blocks (Improve RPCs urls handling #10,000, Add types #1,000,000) with difficulty, total difficulty, extra data
• Post-London blocks (Adding Arbitrum and Optimism and improve Home view #20,000,000) with base fee, burnt fees, withdrawals
• London hard fork boundary blocks (refactpr DataServices base layer #12,964,999, refactpr DataServices base layer #12,965,000)
• More details section with all hash fields (parent hash, state root, transactions root, receipts root, withdrawals root, logs bloom, nonce, mix hash, sha3 uncles)
• Block navigation buttons

Transaction Page (7 tests)

• Legacy (Type 0) transactions - pre-EIP-2718
• EIP-1559 (Type 2) transactions - post-London with maxFeePerGas
• From/to address display and linking
• Transaction value and fee calculations
• Input data and other attributes section
• Block number linking
• Invalid transaction hash handling

Address Page (17 tests)

• EOA accounts with balance and transaction count
• ENS name resolution (vitalik.eth)
• ERC20 token contracts (USDC) with contract details
• Verified contracts (Uniswap Router) with bytecode section

ERC721 (BAYC) tests:

• Collection details (name, symbol, 10,000 NFTs total)
• Contract verification (date, Partial Match, compiler 0.7.0)
• Read functions (21): name, symbol, totalSupply, balanceOf, ownerOf, tokenURI, etc.
• Write functions (16): approve, transferFrom, safeTransferFrom, etc.
• Events (4): Approval, ApprovalForAll, OwnershipTransferred, Transfer

ERC1155 (Rarible) tests:

• Multi-token collection details (name, symbol, metadata URI)
• Contract verification (date, MATCH type, compiler 0.5.17)
• Read functions (16): balanceOf, name, symbol, uri, supportsInterface, etc.
• Write functions (12): mint, burn, safeTransferFrom, setApprovalForAll, etc.
• Events (8): TransferSingle, TransferBatch, ApprovalForAll, URI, etc.

Token Detail Page (12 tests)

ERC721 Token Tests (BAYC #1 and #100):

• NFT Details section (Token ID, Token Standard, Collection Size, Owner)
• Token image display
• Properties/attributes grid with trait types and values
  • BAYC Add types #1: Mouth: Grin, Clothes: Vietnam Jacket, Background: Orange, Eyes: Blue Beams, Fur: Robot
  • BAYC Improve e2e tests #100: Background: Yellow, Mouth: Bored Cigarette, Hat: Party Hat 2, Fur: Dark Brown, Eyes: Wide Eyed
• Token URI section with IPFS link and Open URI button
• Raw Metadata section (expandable)
• Navigation from collection page via token lookup input

ERC1155 Token Tests (Rarible):

• Token details page display
• Balance lookup section (unique to ERC1155)
• Navigation from collection page

Error Handling:

• Invalid token ID handling
• Invalid contract address handling

Infrastructure

• Page Object Model pattern for maintainable tests
• GitHub Actions workflow runs tests on every PR
• Mainnet fixtures indexed by block number and transaction hash
• Headless mode by default (no browser windows opening)
• Graceful error handling for RPC rate limiting and network issues

Files Added/Modified

e2e/
├── fixtures/
│   └── mainnet.ts          # Ethereum mainnet test data
├── pages/
│   ├── address.page.ts     # Address page object
│   ├── block.page.ts       # Block page object
│   └── transaction.page.ts # Transaction page object
└── tests/
    ├── address.spec.ts     # Address page tests
    ├── block.spec.ts       # Block page tests
    ├── token.spec.ts       # Token detail tests
    └── transaction.spec.ts # Transaction page tests

.github/workflows/e2e.yml   # CI workflow
playwright.config.ts        # Playwright configuration
README.md                   # Updated with E2E section

[github-actions]

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