[State Sync Redesign 3.3a] Remove flat state from `controller-init` smart transaction helpers

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`transaction-controller-init.ts` destructures `getFlatState` from the controller init request and passes it to smart transaction selectors (`getIsSmartTransaction`, `getSmartTransactionCommonParams`) and hooks (`publishHook`, `publishBatchHook`). These consume the full flat `ControllerFlatState` type.

With the flat state removal in the PoC (`jongsun/poc/sync-state-redesign`), these call sites are stubbed with `{} as ControllerFlatState`. They need refactoring to read from controllers directly via the messenger.

## Steps

1. Identify which controller properties `publishHook`, `publishBatchHook`, and `isEIP7702GasFeeTokensEnabled` read from flat state
2. Replace `getFlatState()` calls with direct controller state reads via `initMessenger` (e.g., `NetworkController:getState`, `PreferencesController:getState`)
3. Refactor `getSmartTransactionCommonParams` and `getIsSmartTransaction` to accept controller-keyed state or individual controller states instead of `ControllerFlatState`
4. Remove `getFlatState` from the `ControllerInitRequest` type in `controller-init/types.ts` (already done in PoC)
5. Remove `ControllerFlatState` type from `controller-list.ts` if no remaining consumers

## Files

- `app/scripts/controller-init/confirmations/transaction-controller-init.ts`
- `app/scripts/controller-init/types.ts`
- `app/scripts/controller-init/controller-list.ts`
- `shared/modules/selectors/smart-transactions.ts`

## Risk

Medium — smart transaction logic is sensitive. Must validate with E2E swap tests.

## Dependencies

Issue 3.3 (simplify `getState()` to controller-keyed)

## Context

Part of [State Sync Redesign — Epic 3: Background cleanup]. Gap identified during PoC branch `jongsun/poc/sync-state-redesign`.

Start with app/scripts/controller-init/confirmations/transaction-controller-init.ts and trace the flat-state reads into shared/modules/selectors/smart-transactions.ts. Review controller-init/types.ts and controller-list.ts, then inspect the PoC's controller-keyed state approach and the dependency on Issue 3.3. Done means the listed consumers read through initMessenger without ControllerFlatState, unused types are removed, and E2E swap tests pass.

Written by the indexing model from the issue text.