chore(js-ts): Convert all Redux actions and reducers to TypeScript

[devin-ai-integration]

Summary

Converts all 23 remaining JavaScript Redux action and reducer files to TypeScript as part of the JS→TS migration effort.

Actions converted (11 files):

• app/actions/alert, bookmarks, browser, collectibles, infuraAvailability
• app/actions/modals, notification, privacy, settings, transaction, wizard

For each action file:

• Defined action type constants with as const string literal types
• Created discriminated union Action types (e.g., AlertAction, BrowserAction)
• Added explicit parameter and return types to all action creators
• Follows the pattern established in app/actions/onboarding/index.ts

Reducers converted (12 files):

• app/reducers/alert, bookmarks, browser, collectibles, infuraAvailability
• app/reducers/modals, notification, privacy, settings, swaps, transaction, wizard

For each reducer file:

• Defined and exported State interfaces (e.g., AlertState, BrowserState, SwapsState)
• Imported Action union types from corresponding action files
• Typed reducer function signatures: (state: XState, action: XAction) => XState

RootState updated:

• Replaced 12 any types with proper State interfaces in app/reducers/index.ts
• Removed corresponding // TODO: Replace "any" with type and eslint-disable comments

Review & Testing Checklist for Human

• Verify all action creators still produce the correct action shapes (no behavioral changes)
• Verify all reducer state shapes match the original initialState objects
• Check that the swaps reducer (most complex, 420+ lines with selectors) compiles correctly with yarn tsc --noEmit
• Run yarn test --findRelatedTests on a few key files to confirm test compatibility

Notes

• No logic or behavior changes — this is a pure type annotation migration
• The swaps/index.ts reducer is the most complex conversion with many createSelector calls and dynamic chain-ID-keyed state
• The @typescript-eslint/default-param-last eslint-disable is preserved in reducer files since Redux reducers require (state = initialState, action) signature

Link to Devin session: https://app.devin.ai/sessions/51734166b8b740daa75579e47f5a94be
Requested by: @lukepage-COG

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[devin-ai-integration]

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