bug: inconsistent (window as any).ethereum mock setup in Playwright specs

[nanaf6203-bit]

Summary

(window as any).ethereum is mocked in multiple e2e specs but never explicitly cleaned up between files; some specs reassign and others delete, leaving inconsistent state.

Affected area

• tests/e2e/wallet-connection.spec.ts (delete (window as any).ethereum only after the suite)
• tests/e2e/property-purchase-flow.spec.ts (sets (window as any).ethereum and never deletes)
• tests/e2e/property-purchase.spec.ts
• tests/e2e/visual-regression.spec.ts
• tests/e2e/accessibility.spec.ts

Steps to reproduce / impact

When specs run in parallel or in a different order than designed, the global (window as any).ethereum mock leaks between tests, producing flakes and silent state corruption. Wiping inconsistently can also leave isMetaMask / isCoinbaseWallet truthy when the underlying provider wasn't actually installed.

Expected behaviour

A central tests/e2e/wallet-fixture.ts (or Playwright addInitScript) installs a fresh mock on every page navigation and tears it down deterministically.

Acceptance criteria

• A single shared fixture is used for wallet snapshotting.
• window.ethereum is reset before each test.
• No spec edits (window as any).ethereum directly.
• Add a regression test that runs two specs in parallel and verifies no leaked mock.

[OluRemiFour]

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I've reviewed the issue and understand the requirements. I'd love to work on this and submit a clean PR that meets the acceptance criteria.

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[JamesEjembi]

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i would like to work on this issue

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