fix(desktop): 模型输出渲染图表 + Markdown 支持表格/代码围栏；ReAct 步数提至可配 12

针对运行页输出的两个渲染缺口 + 一个节点报错：
- 图表：模型输出走 chart 块分段渲染（文本 Markdown，```chart 块用 ChartView 出图），
  不再把图表 spec 显示成原始代码。
- 表格：轻量 Markdown 组件原本不支持 GFM 表格（| … | 显示成原始竖线）与 ``` 围栏代码，
  现补上：表格解析成 <table>、围栏渲染成 <pre>。
- ReAct 步数：reactMaxStep 由常量 8 改 env 可配（REACT_MAX_STEP，默认 12）。研究型任务
  （搜索→抓取→推理多轮）8 步偏紧易触顶报 exceeds max steps；提到 12 覆盖多数。

tsc+vite 通过，dispatcher build/vet 绿；wails 重启加载。

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

sundynix-desktop/frontend/src/components/Markdown.tsx

@@ -37,8 +37,37 @@ export function Markdown({ text, className, onLink }: { text: string; className?
   const blocks: ReactNode[] = [];
   let para: string[] = [];
   let list: { ordered: boolean; items: string[] } | null = null;
+  let tableBuf: string[] = []; // 连续的 | … | 行，flush 时判定是否真表格
+  let code: { lang: string; lines: string[] } | null = null; // ``` 围栏代码块
   let k = 0;
 
+  const cells = (r: string) => r.replace(/^\s*\|/, "").replace(/\|\s*$/, "").split("|").map((c) => c.trim());
+  const isSep = (s: string) => s.includes("-") && /^\s*\|?[\s:|-]+\|?\s*$/.test(s);
+  const flushTable = () => {
+    if (!tableBuf.length) return;
+    if (tableBuf.length >= 2 && isSep(tableBuf[1])) {
+      const head = cells(tableBuf[0]);
+      const rows = tableBuf.slice(2).map(cells);
+      blocks.push(
+        <div key={`tw${k++}`} className="my-2 overflow-x-auto">
+          <table className="w-full border-collapse text-[13px]">
+            <thead>
+              <tr>{head.map((c, i) => <th key={i} className="border border-line bg-ink-800 px-2 py-1 text-left font-medium text-slate-200">{il(c, `th${k}-${i}`)}</th>)}</tr>
+            </thead>
+            <tbody>
+              {rows.map((r, ri) => (
+                <tr key={ri}>{r.map((c, ci) => <td key={ci} className="border border-line px-2 py-1 align-top text-slate-300">{il(c, `td${k}-${ri}-${ci}`)}</td>)}</tr>
+              ))}
+            </tbody>
+          </table>
+        </div>,
+      );
+    } else {
+      para.push(...tableBuf); // 不是合法表格 → 当普通段落
+    }
+    tableBuf = [];
+  };
+
   const flushPara = () => {
     if (para.length) {
       blocks.push(
@@ -67,20 +96,43 @@ export function Markdown({ text, className, onLink }: { text: string; className?
     }
   };
 
+  const flushAll = () => { flushTable(); flushPara(); flushList(); };
+
   for (const raw of lines) {
     const line = raw.trimEnd();
+
+    // 围栏代码块 ```lang … ```（含未被图表分流的普通代码）。
+    if (code) {
+      if (line.trim().startsWith("```")) {
+        blocks.push(<pre key={`c${k++}`} className="my-2 overflow-x-auto rounded-md border border-line bg-ink-950/60 p-2.5 font-mono text-[12px] leading-relaxed text-slate-300">{code.lines.join("\n")}</pre>);
+        code = null;
+      } else code.lines.push(raw);
+      continue;
+    }
+    if (line.trim().startsWith("```")) {
+      flushAll();
+      code = { lang: line.trim().slice(3), lines: [] };
+      continue;
+    }
+    // 表格行：连续的 | … | 缓冲，flush 时判定真伪。
+    if (line.trim().startsWith("|")) {
+      flushPara();
+      flushList();
+      tableBuf.push(line);
+      continue;
+    }
+
     const h = /^(#{1,3})\s+(.*)$/.exec(line);
     const ol = /^\d+\.\s+(.*)$/.exec(line);
     const ul = /^[-*]\s+(.*)$/.exec(line);
 
     if (line.trim() === "") {
-      flushPara();
-      flushList();
+      flushAll();
     } else if (/^(---|\*\*\*|___)\s*$/.test(line)) {
-      flushPara();
-      flushList();
+      flushAll();
       blocks.push(<hr key={`hr${k++}`} className="my-3 border-line" />);
     } else if (h) {
+      flushTable();
       flushPara();
       flushList();
       const lvl = h[1].length;
@@ -88,14 +140,14 @@ export function Markdown({ text, className, onLink }: { text: string; className?
       const content = il(h[2], `h${k}`);
       blocks.push(lvl === 1 ? <h1 key={`h${k++}`} className={cls}>{content}</h1> : lvl === 2 ? <h2 key={`h${k++}`} className={cls}>{content}</h2> : <h3 key={`h${k++}`} className={cls}>{content}</h3>);
     } else if (line.startsWith(">")) {
-      flushPara();
-      flushList();
+      flushAll();
       blocks.push(
         <blockquote key={`q${k++}`} className="my-2 border-l-2 border-brand/50 pl-3 text-sm text-slate-400">
           {il(line.replace(/^>\s?/, ""), `q${k}`)}
         </blockquote>,
       );
     } else if (ol) {
+      flushTable();
       flushPara();
       if (!list || !list.ordered) {
         flushList();
@@ -103,6 +155,7 @@ export function Markdown({ text, className, onLink }: { text: string; className?
       }
       list.items.push(ol[1]);
     } else if (ul) {
+      flushTable();
       flushPara();
       if (!list || list.ordered) {
         flushList();
@@ -110,12 +163,13 @@ export function Markdown({ text, className, onLink }: { text: string; className?
       }
       list.items.push(ul[1]);
     } else {
+      flushTable();
       flushList();
       para.push(line);
     }
   }
-  flushPara();
-  flushList();
+  if (code) blocks.push(<pre key={`c${k++}`} className="my-2 overflow-x-auto rounded-md border border-line bg-ink-950/60 p-2.5 font-mono text-[12px] text-slate-300">{code.lines.join("\n")}</pre>);
+  flushAll();
 
   return <div className={className}>{blocks}</div>;
 }