fix(connect-a-wallet-widget): harden wallet flows and QA (#245)

[edehvictor]

Closes #245. Follow-up to #116, targeting plan/connect-a-wallet-widget.

Changes

• Use independent HTTP clients for Fuse, Celo and XDC status reads; keep signing on the host wallet provider.
• Show invalid-address feedback that clears on edit, and guard competing chain actions/address changes until the current request settles.
• Cover cancellation, wallet rejection, reverted receipts, wallet changes and RPC failures with SDK-backed mocked interactions.
• Clarify tracked widget screenshots versus ignored root Playwright artifacts. No SDK, shared-core, dependency or lockfile changes.

Verification

• Install passed using pinned pnpm 9.15.0 and a local Windows store.
• Widget build and scoped lint passed. The targeted build used locally emitted dependency declarations because the clean workspace build is blocked below.
• pnpm test:demo tests/widgets/connect-a-wallet-widget --workers=1 --retries=0: 27/27 passed, exit 0.
• Contributor-operated GoodWallet QA covered Celo link/unlink, cancellation, wallet rejection and persistence after refresh. The unlink receipt independently returned success.
• pnpm build and pnpm lint remain blocked by the existing UI Select.tsx:7 Role type error, reproduced from unchanged base commit 3ce69ab6.

Evidence And Limits

Details: QA report.
Evidence: screenshots, including automated desktop/mobile states and a separately labeled manual Celo screenshot.

• Live Fuse/XDC transactions and physical-phone wallet flows were not tested.
• GoodWallet QA used an ignored local WalletConnect chain-ID normalizer: UniversalProvider returned numeric 42220, which shared core parsed as hexadecimal. The shared-core correction is not included outside this issue's scope. These results do not establish unmodified WalletConnect compatibility.
• No private keys, local connection configuration or debug logs are included.

Implementation commit: 074b54799578d08c1c50a492c53061397efd9fd0 (GPG-signed).