feat: make form state persistent between route changes

[necipsagiro]

continuation of babylonlabs-io/simple-staking#1525

i realized we can use the onChange prop on Form component, so changed the logic from functional component to current version.

solved the type inconsistency by introducing a new type StakingFormFields. this is required because we can't directly use FormData since the StakingForm expects validatorAddresses.

[Copilot]

Pull Request Overview

This PR implements form state persistence across route changes by introducing a FormPersistenceState that maintains draft data for both BTC and Baby staking forms. The solution uses the onChange prop on Form components to continuously save form data to React state.

• Adds FormPersistenceState context to store draft form data in memory
• Modifies Tabs component to support keepMounted prop for maintaining component state
• Updates forms to use defaultValues from persisted drafts and save changes via onChange handlers

Reviewed Changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
services/simple-staking/src/ui/common/state/index.tsx	Registers FormPersistenceState in state provider list
services/simple-staking/src/ui/common/state/FormPersistenceState.tsx	New state context for persisting BTC and Baby staking form drafts
services/simple-staking/src/ui/common/page.tsx	Enables keepMounted prop on main Tabs component
services/simple-staking/src/ui/common/components/Tabs/Tabs.tsx	Adds keepMounted option to render all tab content with visibility control
services/simple-staking/src/ui/common/components/Staking/FeeModal/index.tsx	Adds currentFeeRate prop to initialize modal state based on current form values
services/simple-staking/src/ui/common/components/Multistaking/MultistakingForm/StakingFeesSection.tsx	Removes automatic fee rate initialization and passes current rate to FeeModal
services/simple-staking/src/ui/common/components/Multistaking/MultistakingForm/MultistakingForm.tsx	Integrates form persistence with defaultValues and onChange handler
services/simple-staking/src/ui/baby/widgets/StakingForm/index.tsx	Adds StakingFormFields type and integrates form persistence for Baby staking
services/simple-staking/src/ui/baby/layout.tsx	Enables keepMounted for Baby staking tabs

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[gbarkhatov]

Approved with minor suggestions, @jeremy-babylonlabs @jrwbabylonlab @jonybur please also check