feat(11-01): UIE-02 — dedicated Add Printer page at GET /printers/new

- Create imptune/templates/printers_new.html: full page extending base.html
  with plain <form action="/printers" method="post"> (no HTMX, browser follows 303)
  and inline driver upload sub-form
- Update imptune/templates/printers.html: remove inline Add Printer form,
  add <a href="/printers/new" role="button">Add Printer</a> link
- Add GET /printers/new route in imptune/api/pages.py (placed before /{printer_id})
- Change POST /printers to always return RedirectResponse(url='/printers', status_code=303)
- Update existing POST /printers tests to assert 303 + follow_redirects=False
- Update test_printer_form.py to check /printers/new instead of /printers (UIE-02 arch)
- UIE-02 tests GREEN; UIE-01/03 scaffolds remain RED (expected — not yet implemented)

imptune/api/pages.py

@@ -85,6 +85,23 @@ def printers_page(request: Request):
     )
 
 
+@router.get("/printers/new", response_class=HTMLResponse)
+def printers_new_page(request: Request):
+    from imptune.db.models import Client, Driver
+
+    clients = list(Client.select().order_by(Client.name))
+    all_drivers = list(Driver.select().order_by(Driver.uploaded_at.desc()))
+    driver_data = [
+        {"driver": d, "names": json.loads(d.driver_desc) if d.driver_desc else []}
+        for d in all_drivers
+    ]
+    return templates.TemplateResponse(
+        request=request,
+        name="printers_new.html",
+        context={"clients": clients, "driver_data": driver_data},
+    )
+
+
 @router.get("/printers/{printer_id}", response_class=HTMLResponse)
 def printer_detail(request: Request, printer_id: int):
     from imptune.db.models import Client, Driver, Icon, Printer