feat: add fluid-controlled map interfaces

[jenn-le]

Adds fluid-controlled map interfaces, FluidMap and FluidReadonlyMap for extension by interfaces that want APIs that behave closely to TypeScript maps. These are provided to reduce the risk of changes to the built in map breaking downstream customers.

TreeIndex is changed to use FluidReadonlyMap and TreeMapNodeAlpha is added which extends FluidReadonlyMap instead of ReadonlyMap.

[Copilot]

Pull request overview

Introduces Fluid-controlled map-like interfaces (to decouple public APIs from TypeScript lib Map/ReadonlyMap changes) and updates existing map/indexing interfaces to extend the new types.

Changes:

• Added FluidMapLegacy (@public), FluidReadonlyMap (@Alpha), and FluidMap (@Alpha) in @fluidframework/core-interfaces.
• Updated IDirectory, ISharedMap, and TreeIndex to extend FluidMapLegacy / FluidReadonlyMap instead of built-in Map / ReadonlyMap.
• Re-exported the new types across relevant packages and updated API reports + changeset.

Reviewed changes

Copilot reviewed 23 out of 23 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
packages/framework/fluid-framework/src/index.ts	Re-exports FluidMapLegacy from the framework entrypoint.
packages/framework/fluid-framework/api-report/fluid-framework.public.api.md	API report updated to include FluidMapLegacy.
packages/framework/fluid-framework/api-report/fluid-framework.legacy.public.api.md	API report updated; IDirectory now extends FluidMapLegacy.
packages/framework/fluid-framework/api-report/fluid-framework.legacy.beta.api.md	API report updated; IDirectory/ISharedMap now extend FluidMapLegacy.
packages/framework/fluid-framework/api-report/fluid-framework.beta.api.md	API report updated to include FluidMapLegacy.
packages/framework/fluid-framework/api-report/fluid-framework.alpha.api.md	API report updated; adds FluidReadonlyMap and updates TreeIndex to extend it.
packages/dds/tree/src/index.ts	Re-exports FluidReadonlyMap for tree consumers.
packages/dds/tree/src/feature-libraries/indexing/types.ts	Updates TreeIndex to extend FluidReadonlyMap.
packages/dds/tree/api-report/tree.alpha.api.md	API report updated; TreeIndex now extends FluidReadonlyMap.
packages/dds/map/src/interfaces.ts	Updates IDirectory/ISharedMap to extend FluidMapLegacy.
packages/dds/map/src/index.ts	Re-exports FluidMapLegacy from @fluidframework/map.
packages/dds/map/api-report/map.public.api.md	API report updated to include FluidMapLegacy.
packages/dds/map/api-report/map.legacy.public.api.md	API report updated; IDirectory now extends FluidMapLegacy.
packages/dds/map/api-report/map.legacy.beta.api.md	API report updated; IDirectory/ISharedMap now extend FluidMapLegacy.
packages/dds/map/api-report/map.beta.api.md	API report updated to include FluidMapLegacy.
packages/common/core-interfaces/src/index.ts	Exports FluidMap, FluidMapLegacy, and FluidReadonlyMap.
packages/common/core-interfaces/src/fluidMap.ts	Adds the new Fluid-controlled map interface definitions.
packages/common/core-interfaces/api-report/core-interfaces.public.api.md	API report updated to include FluidMapLegacy.
packages/common/core-interfaces/api-report/core-interfaces.legacy.public.api.md	API report updated to include FluidMapLegacy.
packages/common/core-interfaces/api-report/core-interfaces.legacy.beta.api.md	API report updated to include FluidMapLegacy.
packages/common/core-interfaces/api-report/core-interfaces.legacy.alpha.api.md	API report updated to include FluidMap/FluidReadonlyMap/FluidMapLegacy.
packages/common/core-interfaces/api-report/core-interfaces.beta.api.md	API report updated to include FluidMapLegacy.
.changeset/bright-bananas-yell.md	Adds release notes for the new interfaces and interface inheritance changes.

[ChumpChief]

Thanks for picking this up, it will be nice to stabilize this type :)

[github-actions]

🔗 No broken links found! ✅

Your attention to detail is admirable.

linkcheck output

> fluid-framework-docs-site@0.0.0 ci:check-links /home/runner/work/FluidFramework/FluidFramework/docs
> start-server-and-test "npm run serve -- --no-open" 3000 check-links

1: starting server using command "npm run serve -- --no-open"
and when url "[ 'http://127.0.0.1:3000' ]" is responding with HTTP status code 200
running tests using command "npm run check-links"


> fluid-framework-docs-site@0.0.0 serve
> docusaurus serve --no-open

[SUCCESS] Serving "build" directory at: http://localhost:3000/

> fluid-framework-docs-site@0.0.0 check-links
> linkcheck http://localhost:3000 --skip-file skipped-urls.txt

Crawling...

Stats:
  278943 links
    1879 destination URLs
    2124 URLs ignored
       0 warnings
       0 errors

[CraigMacomber]

Looks good to me.