Own all form styling in components; remove form CSS from input.css

Form controls were styled "at a distance": Django renders bare
<input>/<select>/<textarea>/<label>, so input.css reached in with ID-scoped
#add-form descendant rules plus a global form *:disabled rule and .errorlist.
The #add-form ID specificity forced state rules to climb, needed
:not([data-search-select-search]) carve-outs, and broke on markup changes — it
surfaced as the add_purchase Name/related_game fields not reading as disabled.

Components now own all form styling via utilities on the elements themselves:

- PrimitiveWidgetsMixin stamps INPUT/SELECT/TEXTAREA_CLASS (incl. disabled:
  variants) onto native widgets by type, skipping SearchSelect (self-styled)
  and checkboxes.
- New FormFields(form, *, extras=...) renders label + control + errors + row
  layout with their own classes (replaces form.as_div()); the <form> owns its
  flex layout. extras appends a node into a named field's row (session
  timestamp buttons).
- AddForm/purchase/session render via FormFields; login too — a new
  LoginForm(PrimitiveWidgetsMixin, AuthenticationForm) styles its inputs and
  auth.py renders it via FormFields + a StyledButton (was as_table).
- input.css loses the entire #add-form block, the global :disabled rule, and
  .errorlist. State (disabled:) now lives on the element — no specificity wars,
  no carve-outs, robust to markup edits.

Tests: error rendering uses the component class (not .errorlist); add-form
labels/inputs carry their own classes; e2e login fixtures click the Login
button by text (submit is now a <button>); Name disabled cursor asserted.
CLAUDE.md documents the no-styling-at-a-distance + FormFields conventions.

513 passed; lint/format/ts-check clean.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

games/views/auth.py

@@ -4,29 +4,12 @@ registration/login.html)."""
 from django.contrib.auth import views as auth_views
 from django.http import HttpResponse
 
-from common.components import CsrfInput, Div, Element, Input, Node, Safe
-from common.components.primitives import Td, Tr
+from common.components import CsrfInput, Div, Element, FormFields, Node, StyledButton
 from common.layout import render_page
+from games.forms import LoginForm
 
 
 def _login_content(form, request) -> Node:
-    table = Element(
-        "table",
-        children=[
-            CsrfInput(request),
-            Safe(str(form.as_table())),
-            Tr(
-                children=[
-                    Td(),
-                    Td(
-                        children=[
-                            Input(type="submit", attributes=[("value", "Login")])
-                        ],
-                    ),
-                ],
-            ),
-        ],
-    )
     return Div(
         [("class", "flex items-center flex-col")],
         [
@@ -37,15 +20,25 @@ def _login_content(form, request) -> Node:
             ),
             Element(
                 "form",
-                attributes=[("method", "post")],
-                children=[table],
+                attributes=[
+                    ("method", "post"),
+                    ("class", "flex flex-col gap-3 w-full max-w-sm"),
+                ],
+                children=[
+                    CsrfInput(request),
+                    FormFields(form),
+                    StyledButton([], "Login", type="submit"),
+                ],
             ),
         ],
     )
 
 
 class LoginView(auth_views.LoginView):
-    """Django's LoginView, but the page body is built in Python."""
+    """Django's LoginView, but the page body is built in Python and the form is
+    our `LoginForm` so its inputs self-style like every other form."""
+
+    authentication_form = LoginForm
 
     def render_to_response(self, context, **response_kwargs) -> HttpResponse:
         return render_page(