📁 feat: Integrate SharePoint File Picker and Download Workflow (#8651)

* feat(sharepoint): integrate SharePoint file picker and download workflow
Introduces end‑to‑end SharePoint import support:
* Token exchange with Microsoft Graph and scope management (`useSharePointToken`)
* Re‑usable hooks: `useSharePointPicker`, `useSharePointDownload`,
  `useSharePointFileHandling`
* FileSearch dropdown now offers **From Local Machine** / **From SharePoint**
  sources and gracefully falls back when SharePoint is disabled
* Agent upload model, `AttachFileMenu`, and `DropdownPopup` extended for
  SharePoint files and sub‑menus
* Blurry overlay with progress indicator and `maxSelectionCount` limit during
  downloads
* Cache‑flush utility (`config/flush-cache.js`) supporting Redis & filesystem,
  with dry‑run and npm script
* Updated `SharePointIcon` (uses `currentColor`) and new i18n keys
* Bug fixes: placeholder syntax in progress message, picker event‑listener
  cleanup
* Misc style and performance optimizations

* Fix ESLint warnings

---------

Co-authored-by: Atef Bellaaj <slalom.bellaaj@external.daimlertruck.com>

packages/data-provider/src/config.ts

@@ -597,6 +597,11 @@ export type TStartupConfig = {
   instanceProjectId: string;
   bundlerURL?: string;
   staticBundlerURL?: string;
+  sharePointFilePickerEnabled?: boolean;
+  sharePointBaseUrl?: string;
+  sharePointPickerGraphScope?: string;
+  sharePointPickerSharePointScope?: string;
+  openidReuseTokens?: boolean;
   webSearch?: {
     searchProvider?: SearchProviders;
     scraperType?: ScraperTypes;