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/DatabaseManager.tsx

@@ -34,8 +34,8 @@ export default function DatabaseManager({
   };
 
   return (
-    <div className="space-y-6 md:space-y-8 h-full">
-      <div data-testid="database-info" className="bg-surface/50 border border-slate-800/50 rounded-[2.5rem] p-5 md:p-8 shadow-2xl overflow-hidden relative group transition-all">
+    <div className="space-y-4 md:space-y-5 h-full">
+      <div data-testid="database-info" className="bg-surface/50 border border-slate-800/50 rounded-[2.5rem] p-4 md:p-6 shadow-2xl overflow-hidden relative group transition-all">
         <div className="flex items-center gap-4 mb-6">
           <div className="w-10 h-10 rounded-xl bg-primary/10 flex items-center justify-center text-primary border border-primary/20">
             <Database size={20} />
@@ -60,7 +60,7 @@ export default function DatabaseManager({
                 onClick={onCreateBackup}
                 disabled={isBackingUp}
                 data-testid="backup-button"
-                className="flex items-center gap-2 px-5 py-3 bg-primary hover:bg-blue-600 text-white rounded-xl text-sm font-normal transition-all active:scale-95 disabled:opacity-50 shadow-xl shadow-primary/10 tracking-tight focus-visible:ring-2 focus-visible:ring-primary focus-visible:outline-none"
+                className="flex items-center gap-2 px-5 py-2.5 bg-primary hover:bg-blue-600 text-white rounded-xl text-sm font-normal transition-all active:scale-95 disabled:opacity-50 shadow-xl shadow-primary/10 tracking-tight focus-visible:ring-2 focus-visible:ring-primary focus-visible:outline-none"
                 aria-label="Create database backup"
               >
                {isBackingUp ? <RotateCcw size={14} className="animate-spin" /> : <Database size={14} />}
@@ -70,8 +70,8 @@ export default function DatabaseManager({
         </div>
       </div>
 
-      <div className="bg-surface/50 border border-slate-800/50 rounded-[2.5rem] p-5 md:p-8 shadow-2xl space-y-8">
-        <div className="space-y-6">
+      <div className="bg-surface/50 border border-slate-800/50 rounded-[2.5rem] p-4 md:p-6 shadow-2xl space-y-5">
+        <div className="space-y-4">
           <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">
                <History size={20} />
@@ -82,7 +82,7 @@ export default function DatabaseManager({
               </div>
           </div>
 
-          <div className="grid sm:grid-cols-3 gap-6">
+          <div className="grid sm:grid-cols-3 gap-4">
             <div className="space-y-2">
               <label className="text-xs font-normal text-muted tracking-tight ml-1 flex items-center gap-2">
                 <History size={10} /> Max Backups
@@ -158,7 +158,7 @@ export default function DatabaseManager({
         <div className="grid grid-cols-2 gap-4 pt-2">
            <button
              onClick={onExport}
-             className="flex items-center justify-center gap-2 py-4 bg-background border border-slate-800 hover:border-primary/50 text-primary rounded-2xl text-sm font-normal transition-all active:scale-95 tracking-tight shadow-xl shadow-black/20 focus-visible:ring-2 focus-visible:ring-primary focus-visible:outline-none"
+             className="flex items-center justify-center gap-2 py-3 bg-background border border-slate-800 hover:border-primary/50 text-primary rounded-2xl text-sm font-normal transition-all active:scale-95 tracking-tight shadow-xl shadow-black/20 focus-visible:ring-2 focus-visible:ring-primary focus-visible:outline-none"
              aria-label="Export database"
            >
              <Download size={14} /> Export Database