Fix savings SDK stake flow/errors and add dedicated savings widget demo app

[Copilot]

Integrating savings-sdk in GoodDapp exposed three gaps: noisy RPC stack traces surfaced directly to users, stake attempts racing after approval flow, and weekly rewards showing 0 despite active rewards. This PR tightens SDK transaction/state handling, improves widget error UX including wrong-chain behavior, and adds a focused demo app for savings-widget integration.

• Savings SDK: approval→stake correctness and reward computation

  • In packages/savings-sdk/src/viem-sdk.ts, stake() now enforces a stricter allowance path:
    • wait for approval receipt,
    • require successful approval status,
    • re-check allowance before proceeding to stake.
  • Weekly rewards logic now computes from refreshed global stats when needed and avoids invalid division paths.
  • Added explicit wallet runtime chain check before tx submission to fail fast with a clean wrong-network error.

• Savings Widget: clean user-facing errors + chain-switch UX

  • In packages/savings-widget/src/GooddollarSavingsWidget.ts, transaction errors are normalized to a concise first-line message (stripping contract call/docs/detail noise).
  • Added wrong-chain handling for stake/unstake/claim actions:
    • attempts wallet_switchEthereumChain to Celo (0xa4ec),
    • falls back to clear user messaging if switching fails.
  • Tightened internal error typing and kept messages focused on actionable outcomes (rejected tx, insufficient gas funds, wrong network).

• New demo app for savings-widget

  • Added apps/demo-savings-widget (Vite) to exercise savings widget flows with an injected EIP-1193 wallet.
  • Includes connect wiring, account/chain change handling, and direct provider assignment to <gooddollar-savings-widget>.

• Docs update

  • Added apps/demo-savings-widget to the root workspace demo list in README.md.

// packages/savings-sdk/src/viem-sdk.ts (conceptual flow)
if (allowance < amount) {
  const approvalReceipt = await submitAndWait(approveTx)
  if (approvalReceipt.status !== "success") throw new Error("Approval transaction failed")

  const updatedAllowance = await readAllowance()
  if (updatedAllowance < amount) {
    throw new Error("Approval is still insufficient. Please wait for confirmation and try staking again.")
  }
}

return submitAndWait(stakeTx)

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• binaries.soliditylang.org
  • Triggering command: /usr/local/bin/node /usr/local/bin/node /home/REDACTED/work/GoodSDKs/GoodSDKs/packages/engagement-contracts/node_modules/hardhat/internal/cli/bootstrap.js compile (dns block)
• forno.celo.org
  • Triggering command: /home/REDACTED/.cache/ms-playwright/chromium_headless_shell-1217/chrome-headless-shell-linux64/chrome-headless-shell /home/REDACTED/.cache/ms-playwright/chromium_headless_shell-1217/chrome-headless-shell-linux64/chrome-headless-shell --disable-field-trial-config --disable-REDACTED-networking --disable-REDACTED-timer-throttling --disable-REDACTEDing-occluded-windows --disable-back-forward-cache --disable-breakpad --disable-client-side-phishing-detection --disable-component-extensions-with-REDACTED-pages --disable-component-update --no-default-browser-check --disable-default-apps --disable-dev-shm-usage --disable-extensions --disable-features=AvoidUnnecessaryBeforeUnloadCheckSync,BoundaryEventDispatchTracksNodeRemoval,DestroyProfileOnBrowserClose,DialMediaRouteProvider,GlobalMediaControls,HttpsUpgrades,LensOverlay,MediaRouter,PaintHolding,ThirdPartyStoragePartitioning,Transl in/dist/ripgrep/--disable-client-side-phishing-detection (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
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[edehvictor]

GM @L03TJ3 please kindly assign to me. I can work on this. I'm an experienced open source contributor.

[Franklivania]

Hello @L03TJ3, I am able to take up this task, and improve the functionality on the three gaps. I actively contribute to the stellar ecosystem, and is able to execute with proper cleanup.

Thank you

[kadiray34]

@L03TJ3 We have submitted new PR that contains these changes also.
#49
This can be closed.

[L03TJ3]

Changes proposed are included in this PR: #49
so closing