分享码功能的实现，并修复了几个 bug

client/src/pages/eq/components/FreqChart.tsx

@@ -327,7 +327,7 @@ export function FreqChart({
         >
           {/* dB grid */}
           {gainLabels.map((g) => (
-            <g key={g}>
+            <g key={`gain-${g}`}>
               <line x1="0" y1={gainToY(g)} x2={W} y2={gainToY(g)}
                 stroke="rgba(255,255,255,0.05)" strokeWidth="1" />
               <text x="3" y={gainToY(g) - 2} fontSize="7" fill="rgba(255,255,255,0.2)">
@@ -337,7 +337,7 @@ export function FreqChart({
           ))}
           {/* Freq grid */}
           {freqLabels.map((f) => (
-            <line key={f} x1={freqToX(f)} y1="0" x2={freqToX(f)} y2={H - 12}
+            <line key={`freq-line-${f}`} x1={freqToX(f)} y1="0" x2={freqToX(f)} y2={H - 12}
               stroke="rgba(255,255,255,0.05)" strokeWidth="1" />
           ))}
           {/* Zero line */}
@@ -385,7 +385,7 @@ export function FreqChart({
           {/* Band nodes with index */}
           {showEq && bands.map((band, i) => (
             <g
-              key={i}
+              key={`band-${i}`}
               style={{ cursor: "grab" }}
               onPointerDown={(e) => handleBandPointerDown(i, e)}
             >
@@ -430,7 +430,7 @@ export function FreqChart({
           ))}
           {/* Freq axis labels */}
           {freqLabels.map((f) => (
-            <text key={f} x={freqToX(f)} y={H - 1} textAnchor="middle"
+            <text key={`freq-text-${f}`} x={freqToX(f)} y={H - 1} textAnchor="middle"
               fontSize="7" fill="rgba(255,255,255,0.25)">
               {f >= 1000 ? `${f / 1000}k` : f}
             </text>