Add workspace rules PDF document upload, view, and management UI

[ishpaul777]

Summary

Adds frontend support for workspace admins to upload, replace, view, and delete a PDF document on the workspace overview page. Non-admins can view/download the document.

Changes

• WorkspaceOverviewPage.tsx — Added PDF document section with AttachmentPicker for upload, PDFThumbnail for preview, three-dots menu for replace/delete, and tap-to-view via AttachmentModalScreen
• Policy.ts (actions) — Added updateWorkspaceRulesDocument, deleteWorkspaceRulesDocument actions with optimistic/failure/finally Onyx updates. Uses file.uri (local blob) for optimistic display (same pattern as workspace avatar)
• PolicyUtils.ts — Added getPolicyDocumentSourceURL utility that constructs the authenticated streaming URL with cache-busting parameter, or returns local blob URIs directly
• WorkspaceDocumentModalContent.tsx — New modal content component (mirrors WorkspaceAvatarModalContent) for viewing the PDF in the attachment modal
• Navigation — Added WORKSPACE_DOCUMENT route and screen following the WORKSPACE_AVATAR pattern
• Types — Added policyDocumentURL to Policy.ts type, new API parameter types

Key decisions:

• Optimistic updates use file.uri (local blob URL) for instant display — same proven pattern as workspace avatar uploads
• Cache-busting via &cacheBuster= parameter encoding the full policyDocumentURL — ensures the streaming URL is unique per PDF version, preventing stale browser cache
• Dedicated WORKSPACE_DOCUMENT route instead of reusing REPORT_ATTACHMENTS — workspace documents are not report attachments
• PDF served through authenticated api.php streaming endpoint (not direct CDN) — required for CORS compatibility with pdfjs and for privacy (private S3 bucket)

Fixed Issues

$ https://github.com/Expensify/Expensify/issues/610806

Tests

• Verify this pull request passes all automated checks

Manual tests:

1. As admin: Upload a PDF → verify thumbnail appears immediately
2. Tap thumbnail → verify PDF opens in attachment modal
3. Replace PDF with a different one → verify new thumbnail/content appears immediately
4. Delete PDF → verify it disappears
5. Upload a non-PDF → verify error
6. As non-admin member → verify PDF is viewable but upload/delete options are hidden

[codecov]

Codecov Report

❌ Looks like you've decreased code coverage for some files. Please write tests to increase, or at least maintain, the existing level of code coverage. See our documentation here for how to interpret this table.

Files with missing lines	Coverage Δ
src/SCREENS.ts	100.00% <ø> (ø)
src/libs/API/types.ts	100.00% <ø> (ø)
src/libs/Navigation/AppNavigator/AuthScreens.tsx	83.14% <100.00%> (+0.19%)	⬆️
...ateRootStackNavigator/GetStateForActionHandlers.ts	28.88% <ø> (ø)
src/libs/Navigation/linkingConfig/config.ts	76.92% <ø> (ø)
src/ROUTES.ts	16.32% <0.00%> (-0.02%)	⬇️
src/pages/media/AttachmentModalScreen/index.tsx	25.00% <0.00%> (-2.78%)	⬇️
src/libs/PolicyUtils.ts	61.72% <0.00%> (-0.40%)	⬇️
...dalScreen/routes/WorkspaceDocumentModalContent.tsx	0.00% <0.00%> (ø)
src/pages/workspace/WorkspaceOverviewPage.tsx	0.00% <0.00%> (ø)
... and 1 more
... and 13 files with indirect coverage changes