Add Playwright end-to-end test for full deposit → countdown → unlock flow on testnet

[prodbycorne]

Problem

There are no end-to-end tests. The full user journey — connect wallet → deposit assets → wait for lock countdown → unlock — has never been exercised in CI. Regressions in the Freighter integration, transaction building, or countdown logic can ship undetected.

Expected Behaviour

A Playwright test suite (e2e/farm.spec.ts) exercises the core happy path against a local Soroban testnet (using stellar-cli to start soroban-dev) with a pre-funded test wallet injected via a Freighter-compatible stub.

Acceptance Criteria

• e2e/ directory created with playwright.config.ts targeting http://localhost:3000
• e2e/mocks/freighter.ts exports a Playwright page fixture that intercepts window.__freighter and provides a deterministic signing key (test keypair, never a real key)
• e2e/farm.spec.ts test cases:
  1. Connect wallet — click Connect, mock Freighter returns test public key, header updates to show truncated address
  2. Deposit — fill deposit modal with 10 XLM, mock simulation returns fee 100 stroops, sign and submit mock tx, farm row shows stake "10.0000 XLM"
  3. Countdown visible — farm row shows a non-zero countdown and the Unlock button is disabled
  4. Unlock available — fast-forward the system clock 7 days (page.clock.setFixedTime), reload, Unlock button is enabled
  5. Unlock — fill unlock modal, sign, submit, farm row shows stake "0.0000"
• Tests run in CI via pnpm playwright test in the GitHub Actions workflow (.github/workflows/e2e.yml)
• All five tests pass on the Playwright Chromium headless runner

Relevant Files

• e2e/ — create directory and all test files
• .github/workflows/ — add e2e.yml
• package.json — add @playwright/test devDependency

[joelpeace48-cell]

Hi, just found this issue and I think it's a strong fit. I'd approach it by understanding how {the current behaviour} works today, making the change cleanly, and adding/adjusting tests so the fix is covered. I'll make sure the full pipeline is green before I mark the PR ready. Glad to start as soon as you assign it.

[grantfox-oss]

🦊 GrantFox — @joelpeace48-cell has been assigned to this issue as part of the Official Campaign campaign!

Next steps:

1. Open a Pull Request referencing this issue (e.g., Closes #29)
2. Your PR will be reviewed by the SmartDropLabs maintainers

Good luck! Track your progress on GrantFox.

[grantfox-oss]

🎉 This issue has been marked as completed on GrantFox as part of the Official Campaign campaign!

@joelpeace48-cell's PR #54 was approved and merged by @prodbycorne.

🏆 @joelpeace48-cell: You earned 35 FoxPoints for this contribution! Your current tier: Explorer (191 total points). Track your full progress on GrantFox.

👏 Great work, @joelpeace48-cell! Keep contributing to SmartDropLabs.