fix(mock): prevent mocked module overwrite by new loaded chunk modules

[fi3ework]

Summary

when there are multiple bundled entry points (such as rstest.setup.ts and index.test.ts), the project's module may exist in exports.modules of each chunk, which can lead to the following problem:

load rstest.setup.ts (it mocks module A) ->
module A been mocked ->
load index.test.ts ->
module A is re-installed since it's duplicated in this chunk, so it overwriting the mock ->
mocking module A in index.test.ts will not work

this PR modifies the internal logic of installChunk to no longer forcibly overwrite modules that have already been mocked. and because the use of RemoveDuplicateModulesPlugin has been removed, the overall chunk is now simpler, so the watch test has also been rolled back.

Related Links

Checklist

• Tests updated (or not required).
• Documentation updated (or not required).

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[Copilot]

Pull Request Overview

This PR fixes a critical bug where mocked modules could be overwritten when loading new chunks that contain duplicate module definitions. Previously, when multiple bundled entry points existed, modules present in multiple chunks would be re-installed, overwriting any existing mocks. The solution modifies the chunk loading runtime to skip reinstalling modules that have already been mocked.

Key Changes:

• Modified chunk loading runtime to prevent reinstallation of already-mocked modules
• Removed RemoveDuplicateModulesPlugin configuration as it's no longer needed
• Updated plugin names for better clarity

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

File	Description
packages/core/src/core/rsbuild.ts	Removed RemoveDuplicateModulesPlugin and its import
packages/core/src/core/plugins/moduleCacheControl.ts	Updated plugin names from generic "CustomPlugin" to descriptive names
packages/core/src/core/plugins/mockRuntime.ts	Added runtime module hook to modify chunk loading behavior and prevent mocked module overwrites
e2e/watch/index.test.ts	Updated test expectations to reflect simpler chunk behavior without duplicate module removal

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