Consolidate duplicated Playwright fixtures (msw-fixture vs wallet-fixture)

[nanaf6203-bit]

Context

tests/fixtures/msw-fixture.ts and tests/e2e/wallet-fixture.ts (plus tests/helpers/) overlap in wallet/session mocking and API stub setup, with different patterns used across specs.

Problem

Specs drift in how they mock the chain/API; fixing a mock bug requires touching multiple fixtures, and some specs re-implement mocks inline.

Proposed approach

Create one canonical fixture module exporting wallet and api fixtures (extends Playwright test), migrate specs, delete duplicates, document in tests/README.md.

Acceptance criteria

• Single fixture module used by all specs
• No inline mock duplication (grep-verified)
• E2E suite passes after migration

[mazzam2006]

@mazzam2006 has applied to work on this issue as part of the Stellar Wave Program's 9th wave.

Let me have a shot at this.

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[devkylian-tech]

@devkylian-tech has applied to work on this issue as part of the Stellar Wave Program's 9th wave.

I would like to work on this kindly assign me

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[dDevAhmed]

@dDevAhmed has applied to work on this issue as part of the Stellar Wave Program's 9th wave.

I would like to work on this

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