refactor: optimize spacing and typography (Phase 1 - High-Impact)

DatabaseManager:
- Reduce container spacing: space-y-6 md:space-y-8 → space-y-4 md:space-y-5
- Reduce panel padding: p-5 md:p-8 → p-4 md:p-6
- Reduce inner section spacing: space-y-6 → space-y-4, space-y-8 → space-y-5
- Reduce grid gap: gap-6 → gap-4
- Reduce button heights: Export/Import py-4 → py-3, Force Backup py-3 → py-2.5

LdapManager:
- Reduce container spacing: space-y-6 → space-y-4
- Reduce panel padding: p-5 md:p-8 → p-4 md:p-6
- Reduce grid gaps: gap-4 → gap-3 (2 instances)
- Reduce button heights: py-3 → py-2.5 (Test Connection, Save LDAP Policy)

IdentityManager:
- Reduce panel padding: p-5 md:p-8 → p-4 md:p-6
- Reduce user list spacing: space-y-2.5 → space-y-2
- Reduce modal padding: p-8 → p-6
- Reduce modal header gap: mb-6 → mb-4

Results: ~80px vertical space saved (~7% density gain on 1920px viewport)
All 291 tests passing.

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

frontend/components/admin/IdentityManager.tsx

@@ -24,7 +24,7 @@ export default function IdentityManager({
   onUpdateUserSubmit
 }: IdentityManagerProps) {
   return (
-    <div className="bg-surface/50  border border-slate-800/50 rounded-[2.5rem] p-5 md:p-8 flex flex-col shadow-2xl transition-all group/identity h-full">
+    <div className="bg-surface/50  border border-slate-800/50 rounded-[2.5rem] p-4 md:p-6 flex flex-col shadow-2xl transition-all group/identity h-full">
       <div className="flex items-center justify-between mb-6">
         <div className="flex items-center gap-4">
           <div className="w-10 h-10 rounded-xl bg-primary/10 flex items-center justify-center text-primary border border-primary/20">
@@ -42,7 +42,7 @@ export default function IdentityManager({
         </button>
       </div>
 
-      <div className="flex-1 space-y-2.5 pr-2 -mr-2 overflow-y-auto max-h-[400px] scrollbar-thin scrollbar-thumb-slate-800 scrollbar-track-transparent">
+      <div className="flex-1 space-y-2 pr-2 -mr-2 overflow-y-auto max-h-[400px] scrollbar-thin scrollbar-thumb-slate-800 scrollbar-track-transparent">
         {users.map((user) => (
           <div key={user.id} className="flex items-center justify-between p-3.5 bg-background/40 border border-slate-800/40 rounded-2xl hover:border-primary/30 transition-all group">
             <div className="flex items-center gap-3 min-w-0">
@@ -86,8 +86,8 @@ export default function IdentityManager({
       {/* Edit User Modal */}
       {editingUser && (
         <div className="fixed inset-0 z-[100] flex items-center justify-center p-4 bg-background/80  animate-in fade-in duration-200">
-          <div className="bg-surface border border-slate-800 rounded-[2.5rem] p-8 w-full max-w-md shadow-2xl">
-            <div className="flex justify-between items-center mb-6">
+          <div className="bg-surface border border-slate-800 rounded-[2.5rem] p-6 w-full max-w-md shadow-2xl">
+            <div className="flex justify-between items-center mb-4">
               <h3 className="text-xl font-normal text-white tracking-tight">Edit Identity</h3>
               <button
                 onClick={() => setEditingUser(null)}