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/api/v1/admin.py

@@ -21,7 +21,15 @@ from app.schemas.admin import (
     AdminUserUpdateRequest,
 )
 from app.schemas.setting import SettingResponse, SettingsListResponse, UpdateSettingRequest
-from app.services import context_service, skill_service, setting_service, admin_user_service
+from app.schemas.pdf_template import (
+    CreatePdfTemplateRequest,
+    PdfTemplateListResponse,
+    PdfTemplateResponse,
+    PreviewRequest,
+    PreviewResponse,
+    UpdatePdfTemplateRequest,
+)
+from app.services import context_service, skill_service, setting_service, admin_user_service, pdf_template_service
 
 router = APIRouter(prefix="/admin", tags=["admin"])
 
@@ -150,3 +158,63 @@ async def update_setting(
 ):
     setting = await setting_service.upsert_setting(db, key, data.value, admin.id)
     return SettingResponse.model_validate(setting)
+
+
+# --- PDF Templates ---
+
+@router.get("/pdf-templates", response_model=PdfTemplateListResponse)
+async def list_pdf_templates(
+    _admin: Annotated[User, Depends(require_admin)],
+    db: Annotated[AsyncSession, Depends(get_db)],
+):
+    templates = await pdf_template_service.list_templates(db, active_only=False)
+    return PdfTemplateListResponse(templates=[PdfTemplateResponse.model_validate(t) for t in templates])
+
+
+@router.post("/pdf-templates", response_model=PdfTemplateResponse, status_code=status.HTTP_201_CREATED)
+async def create_pdf_template(
+    data: CreatePdfTemplateRequest,
+    _admin: Annotated[User, Depends(require_admin)],
+    db: Annotated[AsyncSession, Depends(get_db)],
+):
+    template = await pdf_template_service.create_template(db, **data.model_dump())
+    return PdfTemplateResponse.model_validate(template)
+
+
+@router.get("/pdf-templates/{template_id}", response_model=PdfTemplateResponse)
+async def get_pdf_template(
+    template_id: uuid.UUID,
+    _admin: Annotated[User, Depends(require_admin)],
+    db: Annotated[AsyncSession, Depends(get_db)],
+):
+    template = await pdf_template_service.get_template(db, template_id)
+    return PdfTemplateResponse.model_validate(template)
+
+
+@router.patch("/pdf-templates/{template_id}", response_model=PdfTemplateResponse)
+async def update_pdf_template(
+    template_id: uuid.UUID,
+    data: UpdatePdfTemplateRequest,
+    _admin: Annotated[User, Depends(require_admin)],
+    db: Annotated[AsyncSession, Depends(get_db)],
+):
+    template = await pdf_template_service.update_template(db, template_id, **data.model_dump(exclude_unset=True))
+    return PdfTemplateResponse.model_validate(template)
+
+
+@router.delete("/pdf-templates/{template_id}", status_code=status.HTTP_204_NO_CONTENT)
+async def delete_pdf_template(
+    template_id: uuid.UUID,
+    _admin: Annotated[User, Depends(require_admin)],
+    db: Annotated[AsyncSession, Depends(get_db)],
+):
+    await pdf_template_service.delete_template(db, template_id)
+
+
+@router.post("/pdf-templates/preview", response_model=PreviewResponse)
+async def preview_pdf_template(
+    data: PreviewRequest,
+    _admin: Annotated[User, Depends(require_admin)],
+):
+    html = await pdf_template_service.render_preview(data.html_content)
+    return PreviewResponse(html=html)