Initial commit: trueref v0.1.0-SNAPSHOT

Java 21 / Spring Boot 3.5.3 multi-module Maven project.
Hybrid BM25+HNSW search with RRF, cross-encoder reranker,
ONNX Runtime 1.22.0 (CPU + CUDA 12 GPU variants).

trueref-frontend/web/src/lib/components/ToastContainer.svelte

@@ -0,0 +1,67 @@
+<script lang="ts">
+  import { toasts, dismissToast } from '$lib/toast';
+</script>
+
+<div class="toast-stack" aria-live="polite" aria-atomic="false">
+  {#each $toasts as t (t.id)}
+    <div class="toast lvl-{t.level}" role="status">
+      <span class="msg">{t.message}</span>
+      <button class="close" type="button" aria-label="dismiss" onclick={() => dismissToast(t.id)}
+        >×</button
+      >
+    </div>
+  {/each}
+</div>
+
+<style>
+  .toast-stack {
+    position: fixed;
+    bottom: 18px;
+    right: 18px;
+    display: flex;
+    flex-direction: column;
+    gap: 8px;
+    z-index: 1000;
+    pointer-events: none;
+  }
+  .toast {
+    pointer-events: auto;
+    display: flex;
+    align-items: center;
+    gap: 10px;
+    min-width: 260px;
+    max-width: 420px;
+    padding: 10px 12px;
+    border-radius: 8px;
+    border: 1px solid var(--border);
+    background: var(--bg-card);
+    color: var(--fg);
+    box-shadow: 0 6px 20px rgba(0, 0, 0, 0.35);
+    font-size: 13px;
+  }
+  .toast.lvl-error {
+    border-color: color-mix(in srgb, var(--err) 55%, transparent);
+    background: color-mix(in srgb, var(--err) 12%, var(--bg-card));
+  }
+  .toast.lvl-warn {
+    border-color: color-mix(in srgb, var(--warn) 55%, transparent);
+  }
+  .toast.lvl-success {
+    border-color: color-mix(in srgb, var(--ok) 55%, transparent);
+  }
+  .msg {
+    flex: 1;
+    word-break: break-word;
+  }
+  .close {
+    background: none;
+    border: none;
+    color: var(--fg-dim);
+    font-size: 18px;
+    line-height: 1;
+    cursor: pointer;
+  }
+  .close:hover {
+    color: var(--fg);
+  }
+</style>