Left rail: match WorkClaw sizing/weights/container

Measured sidebar parity:
- Container: dropped the aside's px-1 so the rail is the full w-rail 176px
  (was 168px inner); added bg-background (solid #0a0a0a, was transparent);
  padding now 8px 0 24px (pt-2 pb-6).
- Bottom nav (Skills/Apps/Team/Credits): 14px/400 → 12px/500 (text-xs
  font-medium, leading-[1.3]); trailing credits balance likewise.
- Claw-name labels: active 400→600 (font-semibold), inactive 400→500
  (font-medium); kept 12px.
Verified live at 1440: rail width 176, bg rgb(10,10,10), nav 12px/500,
active claw name 12px/600. Rail-wide change → regenerated all 7 visual
baselines; full suite (37) green.

Co-Authored-By: Claude Fable 5 <[email protected]>

frontend/src/components/shell/AgentRosterItem.tsx

@@ -49,10 +49,10 @@ export function AgentRosterItem({
           </span>
         </span>
         <span
-          className={`max-w-full truncate text-xs transition-colors duration-(--duration-normal) ease-app md:group-data-[collapsed=true]/rail:hidden ${
+          className={`max-w-full truncate text-xs leading-[1.3] transition-colors duration-(--duration-normal) ease-app md:group-data-[collapsed=true]/rail:hidden ${
             active
-              ? "text-foreground"
+              ? "font-semibold text-foreground"
-              : "text-muted-foreground group-hover:text-foreground"
+              : "font-medium text-muted-foreground group-hover:text-foreground"
           }`}
         >
           {agent.name}

frontend/src/components/shell/GlobalNavItem.tsx

@@ -25,7 +25,7 @@ export function GlobalNavItem({
     <Link
       href={href}
       aria-current={active ? "page" : undefined}
-      className={`flex h-8 items-center gap-3 rounded-full px-3 text-sm transition-colors duration-(--duration-normal) ease-app md:group-data-[collapsed=true]/rail:justify-center md:group-data-[collapsed=true]/rail:px-0 ${
+      className={`flex h-8 items-center gap-3 rounded-full px-3 text-xs font-medium leading-[1.3] transition-colors duration-(--duration-normal) ease-app md:group-data-[collapsed=true]/rail:justify-center md:group-data-[collapsed=true]/rail:px-0 ${
         active
           ? "text-foreground"
           : "text-muted-foreground hover:bg-hover-bg hover:text-foreground"
@@ -42,7 +42,7 @@ export function GlobalNavItem({
       {trailing != null && (
         <span
           aria-hidden
-          className="ml-auto text-sm md:group-data-[collapsed=true]/rail:hidden"
+          className="ml-auto text-xs font-medium md:group-data-[collapsed=true]/rail:hidden"
         >
           {trailing}
         </span>

frontend/src/components/shell/LeftRail.tsx

@@ -60,7 +60,7 @@ export function LeftRail({ user, roster, creditsBalance }: LeftRailProps) {
       )}
       <aside
         data-collapsed={collapsed ? "true" : "false"}
-        className={`group/rail z-50 flex h-dvh w-rail shrink-0 flex-col px-1 transition-[transform,width] duration-(--duration-normal) ease-app max-md:fixed max-md:bg-background max-md:shadow-edge ${
+        className={`group/rail z-50 flex h-dvh w-rail shrink-0 flex-col bg-background pt-2 pb-6 transition-[transform,width] duration-(--duration-normal) ease-app max-md:fixed max-md:shadow-edge ${
           open ? "max-md:translate-x-0" : "max-md:-translate-x-full"
         } ${collapsed ? "md:w-20" : ""}`}
       >