feat(core): export IEntryNestModule type

[Krishnachaitanyakc]

Summary

• Export the IEntryNestModule type alias from @nestjs/core so consumers can use it to properly type wrapper functions around NestFactory.create(), NestFactory.createMicroservice(), and NestFactory.createApplicationContext()
• Added @publicApi JSDoc tag to the type definition for consistency with other public API exports
• The type was previously internal (type without export) in nest-factory.ts; this change makes it export type and adds it to the barrel export in index.ts

Closes #16633

Test plan

• Verified TypeScript compilation passes (tsc --noEmit)
• Verified all 762 existing unit tests pass (mocha packages/**/*.spec.ts)
• Verified ESLint passes on modified files
• Verified the type is now importable: import { IEntryNestModule } from '@nestjs/core'
• This is a purely additive change (new export); no existing behavior is modified

[coveralls]

Pull Request Test Coverage Report for Build a04ba923-c529-4187-8599-16fa2666a42b

Details

• 1 of 1 (100.0%) changed or added relevant line in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 89.841%

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Totals
Change from base Build 6236cae6-7cf0-4fee-b50e-9546cfab30b0:	0.0%
Covered Lines:	7473
Relevant Lines:	8318

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💛 - Coveralls