fix(physics-2d): account for scale in Box2D joint anchors

[orchid-world]

Summary

• Apply each rigid body's node.worldScale when converting Joint2D.anchor and connectedAnchor to Box2D local anchor units.
• Rebuild joints attached to or connected with a rigid body when that body's scale changes at runtime.
• Add tests for scaled 2D joint anchors and runtime scale updates.

Issue source: https://forum.cocos.org/t/topic/121887

Re: #

Changelog

• Fixed Box2D 2D joint anchor offset when rigid body nodes are scaled.

Re: #

Changelog

• Fixed Box2D 2D joint anchor offset when rigid body nodes are scaled.

---

Continuous Integration

This pull request:

• needs automatic test cases check.

  Manual trigger with @cocos-robot run test cases afterward.

• does not change any runtime related code or build configuration

  If any reviewer thinks the CI checks are needed, please uncheck this option, then close and reopen the issue.

---

Compatibility Check

This pull request:

• changes public API, and have ensured backward compatibility with deprecated features.
• affects platform compatibility, e.g. system version, browser version, platform sdk version, platform toolchain, language version, hardware compatibility etc.
• affects file structure of the build package or build configuration which requires user project upgrade.
• introduces breaking changes, please list all changes, affected features and the scope of violation.

[github-actions]

Code Size Check Report

Wechat (WASM)	Before	After	Diff
2D Empty (legacy pipeline)	1015126 bytes	1015126 bytes	✅ 0 bytes
2D All (legacy pipeline)	2682844 bytes	2683313 bytes	⚠️ +469 bytes
2D All (new pipeline)	2774681 bytes	2775145 bytes	⚠️ +464 bytes
(2D + 3D) All	10032007 bytes	10032469 bytes	⚠️ +462 bytes

Web (WASM + ASMJS)	Before	After	Diff
(2D + 3D) All	16868425 bytes	16868887 bytes	⚠️ +462 bytes

Interface Check Report

! WARNING this pull request has changed these public interfaces:

@@ -48219,8 +48219,15 @@
     }
     export class Joint2D extends Component {
         /**
          * @en
+         * All registered 2D joints.
+         * @zh
+         * 所有已注册的 2D 关节。
+         */
+        static readonly joints: Joint2D[];
+        /**
+         * @en
          * The position of Joint2D in the attached rigid body's local space.
          * @zh
          * 在自身刚体的本地空间中，Joint2D的位置。
          */

[github-actions]

@orchid-world, Please check the result of run test cases:

• Test Platform: PR-Test
• Editor Version: v4.0.0
• Task Result: FAIL
• Task URL: https://cctest.cocos.org/#/reportview/PR-TEST/ef07b6de-6a87-4921-af55-ce28aa2c0b57/-1
• GitHub Action: https://github.com/cocos/cocos4/actions/runs/26138833298

Task Details

Platform	build	boot	runned	crashScene	FailScene
web-mobile	PASS	PASS	FAIL
ios	PASS	PASS	PASS
mac	PASS	PASS	PASS

[github-actions]

@orchid-world, Please check the result of run test cases:

• Test Platform: PR-Test
• Editor Version: v4.0.0
• Task Result: FAIL
• Task URL: https://cctest.cocos.org/#/reportview/PR-TEST/3b3017a3-0753-408c-b1e7-e8e40774b4c7/-1
• GitHub Action: https://github.com/cocos/cocos4/actions/runs/26138833298

Task Details

Platform	build	boot	runned	crashScene	FailScene
windows	PASS	PASS	PASS
android	PASS	PASS	PASS
wechatgame	PASS	FAIL	FAIL

[star-e]

We may use shorter variable names to reduce code size.

[github-actions]

@orchid-world, Please check the result of run test cases:

• Test Platform: PR-Test
• Editor Version: v4.0.0
• Task Result: PASS
• Task URL: https://cctest.cocos.org/#/reportview/PR-TEST/a522cbdb-c2d2-46c9-afcc-bea92fa1a269/-1
• GitHub Action: https://github.com/cocos/cocos4/actions/runs/31452066140

Task Details

[github-actions]

@orchid-world, Please check the result of run test cases:

• Test Platform: PR-Test
• Editor Version: v4.0.0
• Task Result: PASS
• Task URL: https://cctest.cocos.org/#/reportview/PR-TEST/0a042fb7-3ea8-45ae-99fd-edbffe6039a3/-1
• GitHub Action: https://github.com/cocos/cocos4/actions/runs/31452066140

Task Details