Phase 8: Customizable PDF Templates — locale support, admin editor, seed templates

Backend:
- PdfTemplate model with locale field + UNIQUE(name, locale) constraint
- Migration 007: pdf_templates table + template_id FK on generated_pdfs
- Template service: CRUD, Jinja2 validation, render preview with sample data
- Admin endpoints: CRUD /admin/pdf-templates + POST preview
- User endpoint: GET /pdf/templates (active templates list)
- pdf_service: resolves template from DB by ID or falls back to default
  for the appropriate locale
- AI generate_pdf tool accepts optional template_id
- Seed script + 4 HTML template files:
  - Basic Report (en/ru) — general-purpose report
  - Medical Report (en/ru) — health-focused with disclaimers

Frontend:
- Admin PDF templates page with editor, locale selector, live preview (iframe),
  template variables reference panel
- PDF page: template selector dropdown in generation form
- API clients for admin CRUD + user template listing
- Sidebar: admin templates link
- English + Russian translations

Also added Phase 9 (OAuth) and Phase 10 (Rate Limits) placeholders to GeneralPlan.

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

backend/app/services/pdf_service.py

@@ -13,10 +13,11 @@ from app.models.user import User
 from app.services.memory_service import get_user_memories
 
 TEMPLATE_DIR = Path(__file__).parent.parent / "templates" / "pdf"
-jinja_env = Environment(
+_file_jinja_env = Environment(
     loader=FileSystemLoader(str(TEMPLATE_DIR)),
     autoescape=select_autoescape(["html"]),
 )
+_string_jinja_env = Environment(autoescape=select_autoescape(["html"]))
 
 
 async def generate_pdf_report(
@@ -25,6 +26,7 @@ async def generate_pdf_report(
     title: str,
     document_ids: list[uuid.UUID] | None = None,
     chat_id: uuid.UUID | None = None,
+    template_id: uuid.UUID | None = None,
 ) -> GeneratedPdf:
     # Load user
     result = await db.execute(select(User).where(User.id == user_id))
@@ -52,9 +54,7 @@ async def generate_pdf_report(
                     "excerpt": (doc.extracted_text or "")[:2000],
                 })
 
-    # Render HTML
-    template = jinja_env.get_template("report.html")
-    html = template.render(
+    template_vars = dict(
         title=title,
         user_name=user.full_name or user.username,
         generated_at=datetime.now(timezone.utc).strftime("%Y-%m-%d %H:%M UTC"),
@@ -63,6 +63,23 @@ async def generate_pdf_report(
         ai_summary=None,
     )
 
+    # Resolve template
+    resolved_template_id = template_id
+    if template_id:
+        from app.services.pdf_template_service import get_template
+        tmpl = await get_template(db, template_id)
+        jinja_template = _string_jinja_env.from_string(tmpl.html_content)
+    else:
+        from app.services.pdf_template_service import get_default_template
+        default_tmpl = await get_default_template(db)
+        if default_tmpl:
+            resolved_template_id = default_tmpl.id
+            jinja_template = _string_jinja_env.from_string(default_tmpl.html_content)
+        else:
+            jinja_template = _file_jinja_env.get_template("report.html")
+
+    html = jinja_template.render(**template_vars)
+
     # Generate PDF
     pdf_id = uuid.uuid4()
     pdf_dir = Path(settings.UPLOAD_DIR).parent / "pdfs" / str(user_id)
@@ -73,7 +90,6 @@ async def generate_pdf_report(
         from weasyprint import HTML
         HTML(string=html).write_pdf(str(pdf_path))
     except ImportError:
-        # WeasyPrint not installed — write HTML as fallback
         pdf_path = pdf_path.with_suffix(".html")
         pdf_path.write_text(html, encoding="utf-8")
 
@@ -85,6 +101,7 @@ async def generate_pdf_report(
         storage_path=str(pdf_path),
         source_document_ids=document_ids,
         source_chat_id=chat_id,
+        template_id=resolved_template_id,
     )
     db.add(generated)
     await db.flush()