chore: deprecate @microsoft/sharepointembedded-copilotchat-react

The @microsoft/sharepointembedded-copilotchat-react SDK is being
deprecated. This PR removes every consumer of the SDK from the
samples repo so the surface no longer advertises or depends on it.

Removed across three samples (boilerplate-typescript-react,
project-management, legal-docs):
- Copilot chat components, hooks, providers, and services
- The vendored SDK copy and tarball in legal-docs
- The SDK dependency entry in each package.json (lockfiles
  regenerated)
- Copilot-only config (sharePointHostname, COPILOT_CONFIG,
  SharePoint container scopes, copilotTheme), the SharePoint token
  acquisition helpers that only existed to bootstrap the SDK, and
  the dead Vite alias/dedupe blocks added to load the SDK shim
- UI affordances that opened the chat panel (toolbar buttons,
  flyout entries, resizable panels) and their dead CSS
- The AI prompt recipes that targeted this SDK
  (contoso-audit-agent, contoso-legal-agent)

Documentation:
- Root README and Custom Apps README no longer advertise
  "Copilot SDK" / "AI-assisted document review" for legal-docs
- legal-docs README drops the Copilot integration bullet

Verification:
- npm install + npm run build pass for all three samples

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: Greg Joseph

AI/prompts/contoso-audit-agent.md

@@ -7,7 +7,7 @@ Runnable sample applications demonstrating SharePoint Embedded integration patte
 | [boilerplate-react-azurefunction](./boilerplate-react-azurefunction) | React + Azure Functions | Reference boilerplate: SPA with an Azure Functions OBO proxy |
 | [boilerplate-aspnet-webservice](./boilerplate-aspnet-webservice) | C# / ASP.NET Core | Reference boilerplate: server-side MVC app with tenant onboarding |
 | [boilerplate-typescript-react](./boilerplate-typescript-react) | TypeScript + React + Azure Functions | TypeScript variant of the React boilerplate |
-| [legal-docs](./legal-docs) | React + Fluent UI + Copilot SDK | Legal case management with AI-assisted document review |
+| [legal-docs](./legal-docs) | React + Fluent UI | Legal case management sample |
 | [project-management](./project-management) | React + Vite + Tailwind + shadcn-ui | Project collaboration app |
 | [webhook](./webhook) | Node.js | Minimal Graph API change notification listener |
 

AI/prompts/contoso-legal-agent.md

@@ -12,7 +12,6 @@
     "@microsoft/mgt-msal2-provider": "^4.2.1",
     "@microsoft/mgt-react": "^4.2.1",
     "@microsoft/microsoft-graph-client": "^3.0.7",
-    "@microsoft/sharepointembedded-copilotchat-react": "https://download.microsoft.com/download/970802a5-2a7e-44ed-b17d-ad7dc99be312/microsoft-sharepointembedded-copilotchat-react-1.0.9.tgz",
     "@types/node": "^20.12.7",
     "@types/react": "^18.2.79",
     "@types/react-dom": "^18.2.25",

Custom Apps/README.md

@@ -31,10 +31,3 @@ export const SAMPLE_API_SCOPES = SAMPLE_API_CONTAINER_MANAGE
     ? [SAMPLE_API_CONTAINER_MANAGE]
     : undefined;
 
-// sharepoint scopes
-export const SP_CONTAINER_SELECTED = `${Constants.SP_ROOT_SITE_URL}/Container.Selected`;
-
-// embedded chat scopes
-export const CHAT_SCOPES = [
-    SP_CONTAINER_SELECTED
-];