Add RAGAS evaluation web console (FastAPI + vanilla JS)

- webapp/: FastAPI backend with runs/scenarios/evaluations API routers;
  services for run_reader, report_builder, scenario_scanner, task_manager
  (lazy ragas import — server boots even without ragas); Pydantic models
- webapp/static/: single-page console (layout A: left-nav + main area);
  report detail with metric cards, Chart.js distribution histogram,
  grouping table, lowest-score sample review; trigger evaluation + log polling
- webmain.py: uvicorn entry point (alongside existing main.py CLI)
- start.bat: Windows one-click launcher with env checks and auto-browser open
- rag_eval/datasets/: implement missing loader + normalizer modules
  (load_dataset_records, normalize_records) required by evaluator
- scripts/seed_sample_run.py: generate realistic demo run artifacts
- .gitignore: exclude datasets/ data files but keep rag_eval/datasets/ source

Co-Authored-By: Claude Sonnet 4 <noreply@anthropic.com>

webapp/static/js/app.js

@@ -0,0 +1,152 @@
+// app.js — 视图路由、运行列表渲染、健康检查。整个控制台的入口编排。
+
+const App = {
+  currentRunId: null,
+  views: ["runs", "new", "report"],
+  titles: { runs: "运行列表", new: "新建评估", report: "报告详情" },
+
+  // 初始化：绑定导航、加载首屏、启动健康检查。
+  init() {
+    document.querySelectorAll(".nav-item").forEach((btn) => {
+      btn.addEventListener("click", () => App.switchView(btn.dataset.view));
+    });
+    document.getElementById("refresh-btn").addEventListener("click", () => App.refreshCurrent());
+
+    Runner.init();
+    App.switchView("runs");
+    App.checkHealth();
+    setInterval(App.checkHealth, 15000);
+  },
+
+  // 切换主视图，并同步导航高亮与标题。
+  switchView(view) {
+    if (view === "report" && !App.currentRunId) {
+      // 没有选中的运行时，报告页显示占位。
+    }
+    App.views.forEach((name) => {
+      const el = document.getElementById(`view-${name}`);
+      if (el) el.hidden = name !== view;
+    });
+    document.querySelectorAll(".nav-item").forEach((btn) => {
+      btn.classList.toggle("active", btn.dataset.view === view);
+    });
+    document.getElementById("view-title").textContent = App.titles[view] || view;
+    App.activeView = view;
+
+    if (view === "runs") App.loadRuns();
+    if (view === "new") Runner.loadScenarios();
+    if (view === "report") Report.render(App.currentRunId);
+  },
+
+  // 刷新当前视图的数据。
+  refreshCurrent() {
+    App.switchView(App.activeView || "runs");
+  },
+
+  // 加载并渲染运行列表。
+  async loadRuns() {
+    const container = document.getElementById("runs-container");
+    const empty = document.getElementById("runs-empty");
+    container.innerHTML = '<p class="muted">加载中…</p>';
+    try {
+      const data = await API.runs();
+      const runs = data.runs || [];
+      if (runs.length === 0) {
+        container.innerHTML = "";
+        empty.hidden = false;
+        return;
+      }
+      empty.hidden = true;
+      container.innerHTML = "";
+      runs.forEach((run) => container.appendChild(App.renderRunCard(run)));
+    } catch (err) {
+      container.innerHTML = `<p class="muted">加载失败：${App.escape(err.message)}</p>`;
+    }
+  },
+
+  // 构造一张运行卡片。
+  renderRunCard(run) {
+    const card = document.createElement("div");
+    card.className = "run-card";
+    card.addEventListener("click", () => {
+      App.currentRunId = run.run_id;
+      App.enableReportNav();
+      App.switchView("report");
+    });
+
+    const chips = (run.metrics || [])
+      .map((m) => {
+        const val = run.metric_means ? run.metric_means[m] : null;
+        const cls = App.scoreClass(val);
+        const text = val === null || val === undefined ? "n/a" : val.toFixed(2);
+        return `<span class="metric-chip">${App.escape(App.shortMetric(m))} <b class="${cls}">${text}</b></span>`;
+      })
+      .join("");
+
+    card.innerHTML = `
+      <div class="run-card-head">
+        <div class="run-card-title">${App.escape(run.scenario_name || run.run_id)}</div>
+      </div>
+      <div class="run-card-meta">
+        <div>${App.escape(run.mode || "—")} · judge: ${App.escape(run.judge_model || "—")}</div>
+        <div>${run.valid_samples} 有效 / ${run.invalid_samples} 无效 · ${App.escape(App.shortTime(run.finished_at))}</div>
+      </div>
+      <div class="run-card-metrics">${chips}</div>
+    `;
+    return card;
+  },
+
+  // 启用报告导航项（选中运行后）。
+  enableReportNav() {
+    const btn = document.querySelector('.nav-item[data-view="report"]');
+    if (btn) btn.disabled = false;
+  },
+
+  // 根据分值返回 good/warn/bad/na 配色类。
+  scoreClass(value) {
+    if (value === null || value === undefined) return "na";
+    if (value >= 0.8) return "good";
+    if (value >= 0.65) return "warn";
+    return "bad";
+  },
+
+  // 指标名缩写，节省卡片横向空间。
+  shortMetric(name) {
+    const map = {
+      faithfulness: "faith.",
+      answer_relevancy: "ans.rel.",
+      context_recall: "ctx.recall",
+      context_precision: "ctx.prec.",
+    };
+    return map[name] || name;
+  },
+
+  // 截取时间戳到分钟，便于阅读。
+  shortTime(iso) {
+    if (!iso) return "—";
+    return String(iso).replace("T", " ").slice(0, 16);
+  },
+
+  // 简单 HTML 转义，防止注入。
+  escape(text) {
+    const div = document.createElement("div");
+    div.textContent = text == null ? "" : String(text);
+    return div.innerHTML;
+  },
+
+  // 健康检查，更新左下角状态点。
+  async checkHealth() {
+    const dot = document.getElementById("health-dot");
+    const label = document.getElementById("health-text");
+    try {
+      await API.health();
+      dot.className = "dot ok";
+      label.textContent = "服务正常";
+    } catch (_e) {
+      dot.className = "dot bad";
+      label.textContent = "服务离线";
+    }
+  },
+};
+
+document.addEventListener("DOMContentLoaded", App.init);