spb/spb-cloud

UI improvements:
- ExcelPreview: white Excel-like design (green tabs, gray headers), inline cell editing, XLSX save
- WordPreview: Tiptap rich text editor for edit mode, html-docx-js save as .docx
- PdfPreview: persistent SVG annotation overlay (highlight/note/pen) saved to DB
- FileCard: tag color dots, favorite star, colored bg per file type, relative dates

Layout fixes:
- AppShell: h-screen overflow-hidden for sticky sidebar, h-full on columns
- PreviewEngine: lg:left-64 offset in fullscreen to clear sidebar
- WordTiptapEditor: absolute inset-0 layout so toolbar stays visible in fullscreen
- Navigation arrows hidden while editing

AI fixes:
- /api/ai/files: fix session reading (NextResponse.next → new NextResponse), add try/catch
- /api/ai/chat: buildFileBlocks now async; adds Word (mammoth) and Excel (xlsx) extraction
- AiPanel: MarkdownContent component with remark-gfm + react-syntax-highlighter (Prism)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

## New Features

### Password Manager
- Full credential vault with AES-256-GCM encryption (lib/crypto.ts)
- Password generator (length, charset options) + strength checker
- Reveal/copy/edit/delete per entry with favicon icons
- API routes: GET/POST /api/passwords, GET/PATCH/DELETE /api/passwords/[id]
- Sidebar link added under "Mots de passe"

### Shared Spaces
- Users can now create shared folders (not just admin)
- CreateSharedFolderModal with user picker
- Admin management page at /admin/shared-spaces
- SharedSpaceManagement component + SharedBadge UI
- User-facing shared space view at /dashboard/shared-space/[id]
- Full API: list/create/update/delete spaces, members, storage quota

### Change Password
- ChangePasswordModal with current/new/confirm fields + strength indicator
- POST /api/auth/change-password with bcrypt verify & hash
- Button in sidebar footer

## AI Improvements
- Upgraded to claude-sonnet-4-6 with streaming SSE chat
- Multi-turn conversation history support
- react-markdown rendering for assistant messages
- File mention detection: auto-attach PDF/image/text content to chat
- New Analyser tab with file picker; Search results have Analyser/Download/Summarize actions
- Fixed: legacy files with userId=null now included in all AI queries

## Other Improvements
- Word document preview via mammoth.js (WordPreview plugin)
- Colored file type icons in FileCard
- Proper try/catch on all password API routes
- Better error handling in frontend (network errors, non-JSON responses)
- lib/prisma.ts cleanup for hot-reload stability

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Multi-user system with roles (admin/user/viewer), TOTP 2FA authentication,
AI-powered search/chat/OCR/auto-tagging via Claude Sonnet 4.5, AES-256
encrypted storage, backup system, notification system, REST API with
API keys, bulk file operations, folder ZIP download, light/dark theme,
and mobile-first responsive design.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>