fix bottom strip: icon sizing, rail padding, status alignment

Phosphor icons: reduced font size from 0.88 to 0.75 in unit space
and center-aligned paragraph to prevent horizontal stretching.
Icon rail: removed top border, tightened padding (10h/4v from
12h/6v), reduced icon size to 14px to fit the 26px strip. Status
bar: added horizontal padding and vertical center alignment.
Bottom strip row: added top border, crossAxisAlignment.stretch
so all three sections fill the height uniformly. Default app font
bumped from 14 to 15px.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

app/lib/widgets/src/clide_icon_rail.dart

@@ -39,11 +39,8 @@ class _ClideIconRailState extends State<ClideIconRail> {
     final tokens = ClideTheme.of(context).surface;
     return MouseRegion(
       onExit: (_) => setState(() => _hoveredId = null),
-      child: Container(
+      child: SizedBox(
         width: double.infinity,
-        decoration: BoxDecoration(
-          border: Border(top: BorderSide(color: tokens.dividerColor)),
-        ),
         child: Row(
           mainAxisAlignment: MainAxisAlignment.center,
           children: [
@@ -98,7 +95,7 @@ class _RailButton extends StatelessWidget {
           child: GestureDetector(
             onTap: onTap,
             child: Container(
-              padding: const EdgeInsets.symmetric(horizontal: 12, vertical: 6),
+              padding: const EdgeInsets.symmetric(horizontal: 10, vertical: 4),
               decoration: BoxDecoration(
                 border: Border(
                   bottom: BorderSide(
@@ -109,7 +106,7 @@ class _RailButton extends StatelessWidget {
                   ),
                 ),
               ),
-              child: ClideIcon(item.icon, size: 16, color: color),
+              child: ClideIcon(item.icon, size: 14, color: color),
             ),
           ),
         ),