fix(action): 12维操作建议写入action+技术路径action权限保护+RR区间显示修复

- batch parse_response提取【操作建议】→ save_result写action(根治: action字段只有技术路径写,
  旧'盈亏比不足不建议买入'与12维买入分析同框矛盾)
- write_holding_strategy: 技术路径不得覆盖新鲜(<20h)12维 action(与信号权威同级)
- 前端: rr_high>0即显示低~高区间(rr_low=0是合法信息: 区下沿=止损贴底即损)
- server: SEND_FILE_MAX_AGE_DEFAULT=0 禁静态缓存

static/index.html

@@ -453,7 +453,7 @@ function renderWatchlist() {
               <td class="p-3 text-right font-mono text-sm">${priceDisplay}</td>
               <td class="p-3 text-right font-mono text-sm ${chg>=0?'text-green-400':'text-red-400'}">${chg>=0?'+':''}${chg.toFixed(2)}</td>
               <td class="p-3 text-right font-mono text-xs text-slate-300">${buyZone}<br><span class="text-slate-500">损${sl} 盈${tp}</span></td>
-              <td class="p-3 text-right font-mono text-sm ${rr>=1.5?'text-green-400':rr>0?'text-yellow-400':'text-slate-500'}">${rr>0?rr.toFixed(2):'—'}${(s.rr_low&&s.rr_high&&s.rr_low!==s.rr_high)?'<br><span class="text-[10px] text-slate-500">'+s.rr_low.toFixed(2)+'~'+s.rr_high.toFixed(2)+'</span>':''}</td>
+              <td class="p-3 text-right font-mono text-sm ${rr>=1.5?'text-green-400':rr>0?'text-yellow-400':'text-slate-500'}">${rr>0?rr.toFixed(2):'—'}${(s.rr_high>0)?'<br><span class="text-[10px] text-slate-500">'+(s.rr_low||0).toFixed(2)+'~'+s.rr_high.toFixed(2)+'</span>':''}</td>
               <td class="p-3 text-right"><span class="text-xs px-2 py-1 rounded ${signal.includes('买入')?'bg-green-900/50 text-green-300':signal.includes('关注')?'bg-yellow-900/50 text-yellow-300':'bg-slate-800 text-slate-400'}">${signal||'—'}</span></td>
               <td class="p-3 text-right text-xs text-slate-400">${s.position_advice || '—'}</td>
             </tr>