feat(wallet): align power up/down with legacy and display SP

[ety001]

Summary

• Add dedicated Power Up and Power Down wallet modals aligned with wallet-legacy (slider, STEEM amount input, contextual notes, and Basic/Advanced power up recipient flow).
• Show Steem Power as SP across balances, delegations, and delegate/power down forms by converting VESTS using chain globals via a shared useGlobalProps hook.
• Move cancel power down to the STEEM POWER balance menu (immediate broadcast) and add i18n coverage for en/zh/es.

Test plan

• Open STEEM balance → Power Up: verify legacy-style form, balance fill, Basic/Advanced recipient toggle, and successful power up.
• Open STEEM POWER → Power Down: verify slider, amount input, weekly/delegation/warning notes, and successful power down.
• While power down is active, use Cancel Power Down from the STEEM POWER menu and confirm it cancels immediately.
• Delegate SP from the delegate form and confirm amounts are converted from SP to VESTS correctly.
• Confirm balance/delegation displays show SP instead of raw VESTS.
• Run pnpm test and pnpm type-check.