feat: Redis单值结果直接展示+JSON中文格式化+悬浮复制

1. GET/HGET/TTL等单值命令: 直接展示raw值, 不再套table
2. JSON自动检测+格式化(中文正常显示, 2空格缩进)
3. 非JSON值(如false/数字)直接文本展示
4. 代码块右上角悬浮复制按钮(hover显示)
5. 工具栏显示值类型(JSON/String)替代行列数

frontend/src/pages/QueriesPage.tsx

@@ -25,6 +25,11 @@ interface QueryResult {
   rows: Record<string, unknown>[];
   affected_rows: number;
   execution_time_ms: number;
+  cost_ms?: number;
+  raw_value?: boolean;
+  raw_key?: string;
+  raw_text?: string;
+  error?: string;
 }
 
 interface QueryHistoryItem {
@@ -480,9 +485,15 @@ export default function QueriesPage() {
                 </span>
                 <div className="flex items-center gap-3 text-xs dg-text-secondary">
                   <span className="flex items-center gap-1"><Clock className="w-3 h-3" />{result.execution_time_ms || result.cost_ms || 0}ms</span>
-                  <span>{result.rows?.length || 0} 行</span>
-                  <span>{result.columns?.length || 0} 列</span>
-                  {result.rows && result.rows.length > 0 && (
+                  {result.raw_text !== undefined ? (
+                    <span>{result.raw_value ? 'JSON' : typeof result.raw_text === 'string' ? 'String' : 'Value'}</span>
+                  ) : (
+                    <>
+                      <span>{result.rows?.length || 0} 行</span>
+                      <span>{result.columns?.length || 0} 列</span>
+                    </>
+                  )}
+                  {(result.rows?.length > 0 || result.raw_text !== undefined) && (
                     <>
                       <button onClick={handleCopyResult}
                         className="dg-btn dg-btn-ghost dg-btn-sm gap-1">
@@ -498,7 +509,30 @@ export default function QueriesPage() {
               </div>
             </div>
             <div className="p-0">
-              {result.columns && result.columns.length > 0 ? (
+              {result.raw_text !== undefined ? (
+                /* Raw value display (Redis GET/HGET/TTL etc.) */
+                <div className="p-4">
+                  {result.raw_key && (
+                    <div className="text-xs text-[var(--dg-text-muted)] mb-2 font-mono">{result.raw_key}</div>
+                  )}
+                  <div className="relative group">
+                    <pre className={`text-sm leading-relaxed overflow-auto max-h-[450px] p-3 rounded-lg font-mono ${
+                      result.raw_value
+                        ? 'bg-[var(--dg-bg-primary)] text-blue-300 whitespace-pre-wrap break-all'
+                        : 'bg-[var(--dg-bg-primary)] text-[var(--dg-text-primary)] whitespace-pre-wrap break-all'
+                    }`}>{result.raw_value
+                      ? (() => { try { return JSON.stringify(JSON.parse(String(result.raw_text)), null, 2); } catch { return String(result.raw_text); } })()
+                      : String(result.raw_text)
+                    }</pre>
+                    <button onClick={() => {
+                      const text = result.raw_value ? (() => { try { return JSON.stringify(JSON.parse(String(result.raw_text)), null, 2); } catch { return String(result.raw_text); } })() : String(result.raw_text);
+                      navigator.clipboard.writeText(text).then(() => { setCopied(true); setTimeout(() => setCopied(false), 2000); });
+                    }} className="absolute top-2 right-2 dg-btn dg-btn-ghost dg-btn-sm opacity-0 group-hover:opacity-100 transition-opacity">
+                      {copied ? <Check className="w-3.5 h-3.5 text-green-400" /> : <Copy className="w-3.5 h-3.5" />}
+                    </button>
+                  </div>
+                </div>
+              ) : result.columns && result.columns.length > 0 ? (
                 <div ref={resultContainerRef} onScroll={handleResultScroll} className="overflow-auto max-h-[500px]">
                   <table className="w-full text-sm">
                     <thead className="sticky top-0 z-10">