WIP: Port terrain editor from cocos-creator with authoring API and fixes

[doommm]

This pull request primarily updates type definitions and interfaces to improve type safety, extensibility, and support for terrain editing features in the Cocos CLI types package. The most significant changes are the enhancement of asset handler type definitions, introduction of comprehensive terrain-related interfaces, and improvements to the gizmo and service manager interfaces.

Asset Handler Types:

• Changed ASSET_HANDLER_TYPES from a mutable string array to a readonly tuple of string literals, ensuring better type inference and safety for asset handler types. (src/core/assets/@types/interface.ts [1] packages/cocos-cli-types/__tests__/__snapshots__/dts-snapshot.test.ts.snap [2] [3] [4] [5]
• Updated AssetHandlerType to allow both the defined literals and any string, improving extensibility for custom asset handler types. (packages/cocos-cli-types/__tests__/__snapshots__/dts-snapshot.test.ts.snap [1] [2] [3]

Terrain Editing Support:

• Added a comprehensive set of interfaces and types for terrain editing, including block data, brush state, editor state, terrain service API, and related enums. This enables robust type support for terrain features in the editor. (packages/cocos-cli-types/__tests__/__snapshots__/dts-snapshot.test.ts.snap [1] [2]
• Added Terrain to the IServiceManager interface to expose terrain editing services. (packages/cocos-cli-types/__tests__/__snapshots__/dts-snapshot.test.ts.snap packages/cocos-cli-types/tests/snapshots/dts-snapshot.test.ts.snapR6863)
• Exported the new terrain interfaces from the main index file. (src/core/scene/common/index.ts src/core/scene/common/index.tsR19)

Gizmo and Service Improvements:

• Added the getComponentGizmo method to the IGizmoService interface for retrieving gizmo instances by component. (src/core/scene/common/gizmo.ts [1] packages/cocos-cli-types/__tests__/__snapshots__/dts-snapshot.test.ts.snap [2]

Testing and Validation:

• Added a new test to ensure the ASSET_HANDLER_TYPES declaration is preserved as a literal tuple and that AssetHandlerType matches the intended type signature in the generated .d.ts file. (packages/cocos-cli-types/__tests__/dts-snapshot.test.ts packages/cocos-cli-types/tests/dts-snapshot.test.tsR41-R60)

Miscellaneous:

• Minor addition of a missing Terrain import in the snapshot to support new interfaces. (packages/cocos-cli-types/__tests__/__snapshots__/dts-snapshot.test.ts.snap packages/cocos-cli-types/tests/snapshots/dts-snapshot.test.ts.snapR5416)