feat(equipment): member browse + reserve + sidebar link

/equipment lists active equipment for any member with status and the
required-certification gate shown up front (Reserve is disabled when the
item is unavailable or the member is not certified). Reserving opens an
inline start/end/notes form; the action enforces eligibility and
no-overlap server-side. Sidebar gets a member-visible "Equipment" link.

components/app-sidebar.tsx

@@ -136,6 +136,7 @@ export function AppSidebar({ member, roleName, taskBadge = 0, commsBadge = 0, pa
         <NavLink href="/my-forms" label="Forms" icon={FileText} active={isActive('/my-forms')} onClick={onNav} />
         <NavLink href="/profile" label="My profile" icon={UserCircle} active={isActive('/profile')} onClick={onNav} />
         <NavLink href="/classes" label="Classes" icon={GraduationCap} active={pathname === '/classes' || pathname.startsWith('/classes?')} onClick={onNav} />
+        <NavLink href="/equipment" label="Equipment" icon={Hammer} active={pathname === '/equipment' || pathname.startsWith('/equipment?')} onClick={onNav} />
         <NavLink href="/me" label="My access" icon={BadgeCheck} active={isActive('/me')} onClick={onNav} />
         {isAdmin && (
           <NavLink href="/recruitment" label="Recruitment" icon={UserSearch} active={isActive('/recruitment')} onClick={onNav} />