Add Jinja2 web UI with Bootstrap 5 dark theme

- app/templates/: base layout with sidebar nav + 6 pages
  (dashboard, printers, jobs, filaments, todos, pricing)
- app/routers/ui.py: HTML routes querying the DB live
- API routes moved to /api/* prefix
- requirements: jinja2, python-multipart

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

app/routers/ui.py

@@ -0,0 +1,76 @@
+from fastapi import APIRouter, Depends, Request
+from fastapi.responses import HTMLResponse
+from fastapi.templating import Jinja2Templates
+from sqlalchemy.orm import Session
+
+from app.db import get_db
+from app.models.filament import Filament
+from app.models.print_job import JobStatus, PrintJob
+from app.models.printer import Printer, PrinterStatus
+from app.models.pricing import PricingConfig
+from app.models.todo import Todo
+
+router = APIRouter()
+templates = Jinja2Templates(directory="app/templates")
+
+
+@router.get("/", response_class=HTMLResponse)
+def dashboard(request: Request, db: Session = Depends(get_db)):
+    printers = db.query(Printer).order_by(Printer.name).all()
+    return templates.TemplateResponse("dashboard.html", {
+        "request": request,
+        "active": "dashboard",
+        "printers": printers,
+        "total_printers": len(printers),
+        "printing_count": sum(1 for p in printers if p.status == PrinterStatus.printing),
+        "active_jobs": db.query(PrintJob).filter(
+            PrintJob.status.in_([JobStatus.queued, JobStatus.printing])
+        ).count(),
+        "total_filaments": db.query(Filament).count(),
+        "recent_jobs": db.query(PrintJob).order_by(PrintJob.created_at.desc()).limit(5).all(),
+    })
+
+
+@router.get("/printers", response_class=HTMLResponse)
+def printers_page(request: Request, db: Session = Depends(get_db)):
+    return templates.TemplateResponse("printers.html", {
+        "request": request,
+        "active": "printers",
+        "printers": db.query(Printer).order_by(Printer.name).all(),
+    })
+
+
+@router.get("/jobs", response_class=HTMLResponse)
+def jobs_page(request: Request, db: Session = Depends(get_db)):
+    return templates.TemplateResponse("jobs.html", {
+        "request": request,
+        "active": "jobs",
+        "jobs": db.query(PrintJob).order_by(PrintJob.created_at.desc()).all(),
+    })
+
+
+@router.get("/filaments", response_class=HTMLResponse)
+def filaments_page(request: Request, db: Session = Depends(get_db)):
+    return templates.TemplateResponse("filaments.html", {
+        "request": request,
+        "active": "filaments",
+        "filaments": db.query(Filament).order_by(Filament.brand, Filament.material).all(),
+    })
+
+
+@router.get("/todos", response_class=HTMLResponse)
+def todos_page(request: Request, db: Session = Depends(get_db)):
+    return templates.TemplateResponse("todos.html", {
+        "request": request,
+        "active": "todos",
+        "todos": db.query(Todo).order_by(Todo.done, Todo.created_at.desc()).all(),
+    })
+
+
+@router.get("/pricing", response_class=HTMLResponse)
+def pricing_page(request: Request, db: Session = Depends(get_db)):
+    return templates.TemplateResponse("pricing.html", {
+        "request": request,
+        "active": "pricing",
+        "configs": db.query(PricingConfig).order_by(PricingConfig.valid_from.desc()).all(),
+    })