fix(favoritos): stop the header padding from doubling up

Issue 3 (feedback-pruebas): ReorderableListView.padding wrapped
header/rows/footer with a single horizontal value (16), which doubled
up on top of PluriRootHeader's own internal inset -- landing the
title at 36px instead of the 20px every other root uses -- while also
applying card-tier padding to the flat FilaEmisoraPlana rows (row
tier, matching the same widget's fix on Buscar) and leaving the
populated-state top gap at an unwired 4 that didn't match this same
screen's own empty state (0) or the footer CTA's prototype value (8).

Zeroes the list-level padding and gives the header, chip strip, rows,
and footer CTA their own correctly-tiered insets instead.

lib/pantallas/pantalla_favoritos.dart

@@ -174,12 +174,18 @@ class _PantallaFavoritosState extends State<PantallaFavoritos> {
 
     return ReorderableListView(
       buildDefaultDragHandles: false,
-      padding: const EdgeInsets.fromLTRB(
-        PluriLayout.horizontal,
-        4,
-        PluriLayout.horizontal,
-        PluriLayout.bottomChromeInset,
-      ),
+      // Issue 3 (feedback-pruebas): zero horizontal here, matching every
+      // other root's PluriLayout.pageListPadding convention (Alarmas,
+      // Ajustes, and this screen's OWN empty-state branch above).
+      // ReorderableListView.padding wraps header/children/footer UNIFORMLY,
+      // so a single horizontal value here can never be simultaneously right
+      // for PluriRootHeader (self-padded, wants none), the reorderable rows
+      // (want row tier, applied per item below) and the footer CTA (wants
+      // card tier, applied on the footer's own Padding below). The previous
+      // `PluriLayout.horizontal` doubled up on top of PluriRootHeader's own
+      // internal inset, pushing "Favorites" in by 36px instead of the 20px
+      // every other root uses for its title.
+      padding: const EdgeInsets.only(bottom: PluriLayout.bottomChromeInset),
       header: Padding(
         padding: const EdgeInsets.only(bottom: 12),
         child: Column(
@@ -224,17 +230,39 @@ class _PantallaFavoritosState extends State<PantallaFavoritos> {
               ],
             ),
             const SizedBox(height: 12),
-            _FilaChipsGrupos(
-              grupos: gruposVisibles,
-              favoritos: favoritos,
-              seleccionado: seleccionEfectiva,
-              onSeleccionar: (id) => setState(() => _grupoSeleccionadoId = id),
+            // Issue 3 (feedback-pruebas): t4:218 draws this chip strip at
+            // title-tier (20px) horizontal inset, directly on the page
+            // background -- it now needs its OWN inset since the list's
+            // padding no longer supplies one.
+            Padding(
+              padding: const EdgeInsets.symmetric(
+                horizontal: PluriLayout.titleHorizontal,
+              ),
+              child: _FilaChipsGrupos(
+                grupos: gruposVisibles,
+                favoritos: favoritos,
+                seleccionado: seleccionEfectiva,
+                onSeleccionar:
+                    (id) => setState(() => _grupoSeleccionadoId = id),
+              ),
             ),
           ],
         ),
       ),
       footer: Padding(
-        padding: const EdgeInsets.only(top: 4),
+        // Issue 3 (feedback-pruebas): card tier (16, matching every other
+        // screen's dashed CTA) now that the list's own padding no longer
+        // supplies it, plus t4:234's 8px gap above the CTA
+        // (PluriLayout.compactGap) instead of the previous unwired literal
+        // 4 -- the ONLY state of this screen with a nonzero top gap before
+        // its own content used a value that matched neither this screen's
+        // own empty-state branch nor the prototype.
+        padding: const EdgeInsets.fromLTRB(
+          PluriLayout.horizontal,
+          PluriLayout.compactGap,
+          PluriLayout.horizontal,
+          0,
+        ),
         child: _CtaEmisoraPersonalizada(
           onTap: _abrirFormularioEmisoraPersonalizada,
         ),
@@ -244,14 +272,24 @@ class _PantallaFavoritosState extends State<PantallaFavoritos> {
               _onReorder(filtrados, favoritos, oldIndex, newIndex),
       children: [
         for (var i = 0; i < filtrados.length; i++)
-          _FilaFavorito(
+          // Issue 3 (feedback-pruebas): row tier (12), not card tier -- the
+          // key moves to this wrapper (ReorderableListView identifies each
+          // child by its own top-level key) since FilaEmisoraPlana rows are
+          // documented (audit 4.3) as flat, background-less rows, the same
+          // tier Buscar's results list already uses for the same widget.
+          Padding(
             key: ValueKey(filtrados[i].uuid),
-            index: i,
-            emisora: filtrados[i],
-            grupos: gruposVisibles,
-            grupoActual: gruposVisibles.firstWhere(
-              (g) => g.id == filtrados[i].grupoFavoritosId,
-              orElse: () => gruposVisibles.first,
+            padding: const EdgeInsets.symmetric(
+              horizontal: PluriLayout.rowHorizontal,
+            ),
+            child: _FilaFavorito(
+              index: i,
+              emisora: filtrados[i],
+              grupos: gruposVisibles,
+              grupoActual: gruposVisibles.firstWhere(
+                (g) => g.id == filtrados[i].grupoFavoritosId,
+                orElse: () => gruposVisibles.first,
+              ),
             ),
           ),
       ],
@@ -343,7 +381,6 @@ class _FilaChipsGrupos extends StatelessWidget {
 
 class _FilaFavorito extends StatelessWidget {
   const _FilaFavorito({
-    super.key,
     required this.index,
     required this.emisora,
     required this.grupos,