Feat: Fuse -> Celo staking migration: popover + modal on Savings and Stake

[blueogin]

Is your feature request related to a problem? Please describe.

Users with G$ staked on Fuse (GovernanceStakingV2) need to move to Celo Savings. There is no in-app prompt on Savings or Stake when a wallet still has a Fuse governance stake, so migration is easy to miss.

Describe the solution you'd like

On Savings (/savings) and Stake (/stakes, including GoodDAO Staking and the embedded Savings section), detect a non-zero Fuse governance stake for the connected wallet.
If detected, show an inline popover (short copy + CTA). The CTA opens a modal with the migration steps (summary → sign/bridge → success). Do not use a new tab or standalone page as the entry point.
Reuse GoodWidget UI where practical. Contract addresses from deployment.json only.

GoodWallet: same UX on equivalent screens.

Acceptance criteria

• Popover only when Fuse stake > 0; hidden when disconnected or fully migrated
• CTA opens migration modal; no regression to existing SavingsModal / StakeDeposit
• i18n + analytics for prompt, modal, and steps

Describe alternatives you've considered

• Full-page migration route only — rejected as primary entry; modal first, optional route if the wizard is too large
• AppNotice banner only — rejected; product wants popover + modal
• Auto-open modal on load — rejected; popover is non-blocking, modal on explicit CTA

Additional context

[copilot-swe-agent]

The agent encountered an error and was unable to start working on this issue: Please try again later, or contact support if the problem persists. (Request id: 8386:BA627:61C1CC:7D625A:6A1479DA)