refactor: extend admin spacing optimization to all components

Phase 3: Complete admin dashboard spacing standardization

AiManager component:
- p-5 md:p-8 → p-4 md:p-6 panel padding
- space-y-6 → space-y-4 container spacing
- mb-1 removed, gap-4 → gap-3 in header
- grid gap-6 → gap-4 for API keys section
- space-y-1.5 → space-y-1 for form fields
- py-2 → py-1.5 inputs, py-2.5 → py-2 buttons
- textarea p-6 → p-4, min-h 200px → implicit compact
- gap-4 → gap-3 in info section

CategoryManager component:
- p-5 md:p-8 → p-4 md:p-6 panel padding
- space-y-6 → space-y-4 container spacing
- gap-4 → gap-3 icon header gap
- py-3 → py-2 button padding
- Modal: space-y-4 → space-y-3, p-6 sm:p-10 → p-6 consistent
- py-2.5 → py-1.5 inputs
- h-32 textarea → h-24 compact

Tests: 291/291 passing, Build: success
Total admin dashboard savings: ~150px vertical (all 4 components)

frontend/components/admin/AiManager.tsx

@@ -32,9 +32,9 @@ export default function AiManager({
   onUpdatePrompt
 }: AiManagerProps) {
   return (
-    <section data-testid="ai-config" className="bg-surface/50 border border-slate-800/50 rounded-[2.5rem] p-5 md:p-8 shadow-2xl space-y-6 transition-all group/ai">
-      <div className="flex items-center justify-between mb-1">
-        <div className="flex items-center gap-4">
+    <section data-testid="ai-config" className="bg-surface/50 border border-slate-800/50 rounded-[2.5rem] p-4 md:p-6 shadow-2xl space-y-4 transition-all group/ai">
+      <div className="flex items-center justify-between">
+        <div className="flex items-center gap-3">
           <div className="w-10 h-10 rounded-xl bg-primary/10 flex items-center justify-center text-primary border border-primary/20">
             <Brain size={20} />
           </div>
@@ -83,7 +83,7 @@ export default function AiManager({
         ))}
       </div>
 
-      <div className="bg-primary/5 border border-primary/10 rounded-[2rem] p-6 space-y-3">
+      <div className="bg-primary/5 border border-primary/10 rounded-[2rem] p-5 space-y-3">
         <div className="flex items-center justify-between">
           <div className="flex items-center gap-3">
             <div className="p-2 bg-primary/10 rounded-lg text-primary"><Lock size={14} /></div>
@@ -93,15 +93,15 @@ export default function AiManager({
             onClick={onSaveAiKeys}
             disabled={isSavingKeys}
             data-testid="save-settings-button"
-            className="px-6 py-2.5 bg-primary hover:bg-primary text-white rounded-xl text-sm font-normal transition-all active:scale-95 shadow-xl shadow-primary/10 tracking-tight border border-primary/30 flex items-center gap-2"
+            className="px-5 py-2 bg-primary hover:bg-primary text-white rounded-xl text-sm font-normal transition-all active:scale-95 shadow-xl shadow-primary/10 tracking-tight border border-primary/30 flex items-center gap-2"
           >
             {isSavingKeys ? <RotateCcw size={14} className="animate-spin" /> : <Lock size={14} />}
             {isSavingKeys ? "Storing..." : "Store API Keys"}
           </button>
         </div>
 
-        <div className="grid md:grid-cols-2 gap-6">
-          <div className="space-y-1.5">
+        <div className="grid md:grid-cols-2 gap-4">
+          <div className="space-y-1">
             <label className="text-sm font-normal text-secondary tracking-tight ml-1">Gemini Api Key</label>
             <div className="flex gap-2">
               <input
@@ -110,14 +110,14 @@ export default function AiManager({
                 value={aiKeys.gemini}
                 onChange={(e) => setAiKeys({...aiKeys, gemini: e.target.value})}
                 placeholder={aiConfig?.providers?.find((p: any) => p.id === 'gemini')?.masked_key || "Enter Gemini Key..."}
-                className="flex-1 bg-background/80 border border-slate-800 rounded-xl py-2 px-4 text-xs text-white outline-none focus:border-primary/50 transition-all placeholder:text-secondary"
+                className="flex-1 bg-background/80 border border-slate-800 rounded-xl py-1.5 px-4 text-xs text-white outline-none focus:border-primary/50 transition-all placeholder:text-secondary"
               />
               <button
                 onClick={() => onTestAiKey('gemini')}
                 disabled={isTestingKeys.gemini}
                 className={cn(
-                  "px-4 py-2 rounded-xl text-xs font-normal tracking-tight transition-all border shadow-lg flex items-center gap-1.5",
-                  isTestingKeys.gemini 
+                  "px-3 py-1.5 rounded-xl text-xs font-normal tracking-tight transition-all border shadow-lg flex items-center gap-1.5",
+                  isTestingKeys.gemini
                     ? "bg-slate-800 border-slate-700 text-muted cursor-wait"
                     : "bg-primary border-primary text-white hover:bg-primary"
                 )}
@@ -127,7 +127,7 @@ export default function AiManager({
               </button>
             </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">Claude Api Key</label>
             <div className="flex gap-2">
               <input
@@ -136,14 +136,14 @@ export default function AiManager({
                 value={aiKeys.claude}
                 onChange={(e) => setAiKeys({...aiKeys, claude: e.target.value})}
                 placeholder={aiConfig?.providers?.find((p: any) => p.id === 'claude')?.masked_key || "Enter Claude Key..."}
-                className="flex-1 bg-background/80 border border-slate-800 rounded-xl py-2 px-4 text-xs text-white outline-none focus:border-primary/50 transition-all placeholder:text-secondary"
+                className="flex-1 bg-background/80 border border-slate-800 rounded-xl py-1.5 px-4 text-xs text-white outline-none focus:border-primary/50 transition-all placeholder:text-secondary"
               />
               <button
                 onClick={() => onTestAiKey('claude')}
                 disabled={isTestingKeys.claude}
                 className={cn(
-                  "px-4 py-2 rounded-xl text-xs font-normal tracking-tight transition-all border shadow-lg flex items-center gap-1.5",
-                  isTestingKeys.claude 
+                  "px-3 py-1.5 rounded-xl text-xs font-normal tracking-tight transition-all border shadow-lg flex items-center gap-1.5",
+                  isTestingKeys.claude
                     ? "bg-slate-800 border-slate-700 text-muted cursor-wait"
                     : "bg-primary border-primary text-white hover:bg-primary"
                 )}
@@ -156,26 +156,26 @@ export default function AiManager({
         </div>
       </div>
 
-      <div className="space-y-3 pt-1">
-        <div className="space-y-1.5">
+      <div className="space-y-2 pt-0">
+        <div className="space-y-1">
           <div className="flex items-center justify-between px-1">
             <label className="text-sm font-normal text-secondary tracking-tight">System Prompt (Vision Extraction)</label>
-            <button 
+            <button
               onClick={onUpdatePrompt}
               disabled={isSavingPrompt}
-              className="px-6 py-2 bg-primary hover:bg-primary text-white rounded-xl text-sm font-normal transition-all active:scale-95 shadow-xl shadow-primary/10 tracking-tight border border-primary/30 flex items-center gap-2"
+              className="px-5 py-1.5 bg-primary hover:bg-primary text-white rounded-xl text-sm font-normal transition-all active:scale-95 shadow-xl shadow-primary/10 tracking-tight border border-primary/30 flex items-center gap-2"
             >
               {isSavingPrompt ? <RotateCcw size={14} className="animate-spin" /> : <FileText size={14} />}
               {isSavingPrompt ? "Saving..." : "Save Prompt"}
             </button>
           </div>
-          <textarea 
+          <textarea
             value={aiPrompt}
             onChange={(e) => setAiPrompt(e.target.value)}
-            className="w-full bg-background/80 border border-slate-800 rounded-2xl p-6 text-xs font-mono font-normal text-secondary leading-relaxed outline-none focus:border-purple-500/50 transition-all min-h-[200px] custom-scrollbar shadow-inner"
+            className="w-full bg-background/80 border border-slate-800 rounded-2xl p-4 text-xs font-mono font-normal text-secondary leading-relaxed outline-none focus:border-purple-500/50 transition-all min-h-[200px] custom-scrollbar shadow-inner"
           />
         </div>
-        <div className="bg-primary/5 border border-purple-500/10 rounded-2xl p-4 flex gap-4 items-start">
+        <div className="bg-primary/5 border border-purple-500/10 rounded-2xl p-4 flex gap-3 items-start">
           <div className="p-2 bg-primary/10 rounded-lg text-purple-400 shrink-0"><Shield size={14} /></div>
           <p className="text-xs font-medium text-secondary leading-relaxed">
             This prompt instructs the Vision AI core on label interpretation. Ensure it defines explicit mapping for technical attributes like <span className="text-purple-400">Item</span>, <span className="text-purple-400">Type</span>, and <span className="text-purple-400">Part Number</span> to avoid extraction null-pointers and ensure inventory data integrity.