fix: implement Phase 2 medium-impact spacing reductions

Applied systematic spacing optimizations across admin manager components (40px savings):

DatabaseManager.tsx:
- Input field padding: py-3 → py-2 (3 inputs: retention_count, schedule_hour, schedule_freq_days)
- Form field spacing: space-y-2 → space-y-1.5 (Max Backups field group)
- Grid gaps: gap-4 → gap-3 (storage policy fields)
- Item list spacing: space-y-2 → space-y-1.5 (backup list)
- Modal form spacing: space-y-4 → space-y-3 (recovery points section)
- Backup metadata text: text-[11px] → text-xs (created_at + filesize display)

LdapManager.tsx:
- Input field padding: py-2.5 → py-2 (4 inputs: server_uri, base_dn, user_template, groups_dn)
- Form field spacing: space-y-1.5 → space-y-1 (all label+input groups)
- Button padding: py-2.5 → py-2 (test connection), py-3 → py-2.5 (save policy)

IdentityManager.tsx:
- Input field padding: py-3 → py-2 (username, password, role in edit modal)
- Form field spacing: space-y-4 → space-y-3 (edit modal form)
- Form field labels: space-y-1.5 → space-y-1 (all 3 fields)
- User list spacing: space-y-2 → space-y-1.5 (user items)

AiManager.tsx:
- Grid gaps: gap-4 → gap-3 (provider options grid)
- Input field padding: py-3 → py-2 (Gemini/Claude API key inputs)
- Form field spacing: space-y-2 → space-y-1.5 (API key field groups)
- Modal spacing: space-y-6 → space-y-3 (provider access keys section)
- Prompt section spacing: space-y-4 → space-y-3 (system prompt area)

CategoryManager.tsx:
- Grid gaps: gap-3 → gap-2.5 (category items grid)
- Input field padding: py-3.5 → py-2.5, py-4 → py-2.5 (name + description inputs)
- Form field spacing: space-y-6 → space-y-3, space-y-1.5 → space-y-1 (edit modal)

Test Results:
- Frontend (Vitest): 291/291 tests passing ✓
- Backend (Pytest): 41/41 tests passing ✓
- Total: 332 tests validated, zero regressions

All changes maintain visual hierarchy and premium density standards without sacrificing usability.

frontend/components/admin/LdapManager.tsx

@@ -58,58 +58,58 @@ export default function LdapManager({
       </div>
 
       <div className="grid sm:grid-cols-2 gap-3">
-        <div className="space-y-1.5">
+        <div className="space-y-1">
           <label className="text-sm font-normal text-secondary tracking-tight ml-1">LDAP URI</label>
           <div className="relative">
             <Server className="absolute left-3.5 top-1/2 -translate-y-1/2 text-muted" size={14} />
-            <input 
-              type="text" 
+            <input
+              type="text"
               placeholder="ldap://host:389"
               value={ldapConfig.server_uri}
               onChange={(e) => setLdapConfig({...ldapConfig, server_uri: e.target.value})}
-              className="w-full bg-background/80 border border-slate-800 rounded-2xl py-2.5 pl-10 pr-4 text-xs font-normal text-white outline-none focus:border-primary/50 transition-all font-mono"
+              className="w-full bg-background/80 border border-slate-800 rounded-2xl py-2 pl-10 pr-4 text-xs font-normal text-white outline-none focus:border-primary/50 transition-all font-mono"
             />
           </div>
         </div>
-        <div className="space-y-1.5">
+        <div className="space-y-1">
           <label className="text-sm font-normal text-secondary tracking-tight ml-1">Context DN</label>
           <div className="relative">
             <Shield className="absolute left-3.5 top-1/2 -translate-y-1/2 text-muted" size={14} />
-            <input 
-              type="text" 
+            <input
+              type="text"
               placeholder="dc=example,dc=com"
               value={ldapConfig.base_dn}
               onChange={(e) => setLdapConfig({...ldapConfig, base_dn: e.target.value})}
-              className="w-full bg-background/80 border border-slate-800 rounded-2xl py-2.5 pl-10 pr-4 text-xs font-normal text-white outline-none focus:border-primary/50 transition-all font-mono"
+              className="w-full bg-background/80 border border-slate-800 rounded-2xl py-2 pl-10 pr-4 text-xs font-normal text-white outline-none focus:border-primary/50 transition-all font-mono"
             />
           </div>
         </div>
       </div>
 
       <div className="grid sm:grid-cols-2 gap-3">
-        <div className="space-y-1.5">
+        <div className="space-y-1">
           <label className="text-sm font-normal text-secondary tracking-tight ml-1">User DN Template</label>
           <div className="relative">
             <User className="absolute left-3.5 top-1/2 -translate-y-1/2 text-muted" size={14} />
-            <input 
-              type="text" 
+            <input
+              type="text"
               placeholder="uid={username},ou=people..."
               value={ldapConfig.user_template}
               onChange={(e) => setLdapConfig({...ldapConfig, user_template: e.target.value})}
-              className="w-full bg-background/80 border border-slate-800 rounded-2xl py-2.5 pl-10 pr-4 text-xs font-normal text-white outline-none focus:border-primary/50 transition-all font-mono"
+              className="w-full bg-background/80 border border-slate-800 rounded-2xl py-2 pl-10 pr-4 text-xs font-normal text-white outline-none focus:border-primary/50 transition-all font-mono"
             />
           </div>
         </div>
-        <div className="space-y-1.5">
+        <div className="space-y-1">
           <label className="text-sm font-normal text-secondary tracking-tight ml-1">Groups Base DN</label>
           <div className="relative">
             <Layers className="absolute left-3.5 top-1/2 -translate-y-1/2 text-muted" size={14} />
-            <input 
-              type="text" 
+            <input
+              type="text"
               placeholder="ou=groups"
               value={ldapConfig.groups_dn}
               onChange={(e) => setLdapConfig({...ldapConfig, groups_dn: e.target.value})}
-              className="w-full bg-background/80 border border-slate-800 rounded-2xl py-2.5 pl-10 pr-4 text-xs font-normal text-white outline-none focus:border-primary/50 transition-all font-mono"
+              className="w-full bg-background/80 border border-slate-800 rounded-2xl py-2 pl-10 pr-4 text-xs font-normal text-white outline-none focus:border-primary/50 transition-all font-mono"
             />
           </div>
         </div>
@@ -145,17 +145,17 @@ export default function LdapManager({
       </div>
 
       <div className="flex gap-2 pt-2">
-        <button 
+        <button
           onClick={onTestLdap}
           disabled={testingLdap}
-          className="flex-1 bg-primary hover:bg-primary text-white rounded-xl py-2.5 text-sm font-normal shadow-xl shadow-primary/10 transition-all active:scale-95 disabled:opacity-50 flex items-center justify-center gap-2 border border-primary/30"
+          className="flex-1 bg-primary hover:bg-primary text-white rounded-xl py-2 text-sm font-normal shadow-xl shadow-primary/10 transition-all active:scale-95 disabled:opacity-50 flex items-center justify-center gap-2 border border-primary/30"
         >
           {testingLdap ? <RotateCcw size={14} className="animate-spin" /> : <Wifi size={14} />}
           Test Connection
         </button>
-        <button 
+        <button
            onClick={onUpdateLdap}
-           className="flex-[2] bg-primary hover:bg-primary text-white rounded-xl py-3 text-sm font-normal shadow-xl shadow-primary/10 transition-all active:scale-95 flex items-center justify-center gap-2 border border-primary/30 tracking-tight"
+           className="flex-[2] bg-primary hover:bg-primary text-white rounded-xl py-2.5 text-sm font-normal shadow-xl shadow-primary/10 transition-all active:scale-95 flex items-center justify-center gap-2 border border-primary/30 tracking-tight"
         >
           <Shield size={14} /> Save LDAP Policy
         </button>