fix(parser): 节标题锚定解析+脏区间清洗+三值RR

- parse_response: 只认行首【买入区间】【综合结论】等节行(原先取首个关键词行,
  命中修改点段落引用的旧脏值→95~99区间反复写回,17只股票受害);
  信号锚定】后首词,防'观望(不建议买入)'误判; 【买入区间】无→显式清空
- save_result: 区间-现价距离门禁(eh<0.5px或el>1.5px→拒写并清空,不再保留原值养脏)
- recompute_rr: 三值RR(rr_low/rr_ratio中/rr_high,分别对应区下沿/中值/上沿入场)
- 迁移: holding_strategies+rr_low/rr_high列; digest显示RR中(低~高); watch API+前端展示

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):'—'}</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"><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>