Phase 4: Documents & Memory — upload, FTS, AI tools, context injection

Backend:
- Document + MemoryEntry models with Alembic migration (GIN FTS index)
- File upload endpoint with path traversal protection (sanitized filenames)
- Background document text extraction (PyMuPDF)
- Full-text search on extracted_text via PostgreSQL tsvector/tsquery
- Memory CRUD with enum-validated categories/importance, field allow-list
- AI tools: save_memory, search_documents, get_memory (Claude function calling)
- Tool execution loop in stream_ai_response (multi-turn tool use)
- Context assembly: injects critical memory + relevant doc excerpts
- File storage abstraction (local filesystem, S3-swappable)
- Secure file deletion (DB flush before disk delete)

Frontend:
- Document upload dialog (drag-and-drop + file picker)
- Document list with status badges, search, download (via authenticated blob)
- Document viewer with extracted text preview
- Memory list grouped by category with importance color coding
- Memory editor with category/importance dropdowns
- Documents + Memory pages with full CRUD
- Enabled sidebar navigation for both sections

Review fixes applied:
- Sanitized upload filenames (path traversal prevention)
- Download via axios blob (not bare <a href>, preserves auth)
- Route ordering: /search before /{id}/reindex
- Memory update allows is_active=False + field allow-list
- MemoryEditor form resets on mode switch
- Literal enum validation on category/importance schemas
- DB flush before file deletion for data integrity

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

frontend/public/locales/en/translation.json

@@ -90,6 +90,55 @@
     "subtitle": "This context is added to all your AI conversations",
     "placeholder": "Add personal information that the AI should know about you..."
   },
+  "documents": {
+    "upload": "Upload",
+    "drop_or_click": "Drop a file here or click to browse",
+    "doc_type": "Document Type",
+    "no_documents": "No documents uploaded yet.",
+    "download": "Download",
+    "reindex": "Re-extract text",
+    "extracted_text": "Extracted Text",
+    "search_placeholder": "Search documents...",
+    "clear_search": "Clear",
+    "types": {
+      "other": "Other",
+      "lab_result": "Lab Result",
+      "consultation": "Consultation",
+      "prescription": "Prescription",
+      "imaging": "Imaging"
+    },
+    "status": {
+      "pending": "Pending",
+      "processing": "Processing",
+      "completed": "Completed",
+      "failed": "Failed"
+    }
+  },
+  "memory": {
+    "create": "Add Memory Entry",
+    "edit": "Edit Memory Entry",
+    "no_entries": "No memory entries yet. The AI will save important health information here.",
+    "category": "Category",
+    "importance": "Importance",
+    "title_field": "Title",
+    "title_placeholder": "e.g. Diabetes Type 2",
+    "content_field": "Content",
+    "content_placeholder": "Detailed information...",
+    "categories": {
+      "condition": "Condition",
+      "medication": "Medication",
+      "allergy": "Allergy",
+      "vital": "Vital Sign",
+      "document_summary": "Document Summary",
+      "other": "Other"
+    },
+    "importance_levels": {
+      "critical": "Critical",
+      "high": "High",
+      "medium": "Medium",
+      "low": "Low"
+    }
+  },
   "common": {
     "loading": "Loading...",
     "error": "An error occurred",