Implement CE-WP-0002 T03-T09: ingest, anchor resolution, engine, UI, persistence, e2e

Completes the PDF review slice end-to-end. After this commit a user can
open a fixture, select text, save an evidence item with commentary, see
it in the sidebar, reload the page, click the item, and the viewer
scrolls to the passage.

- T03 src/source/pdf/{fingerprint,extract,ingest}.ts + 39 fixture tests
  - SHA-256 fingerprint over a fresh ArrayBuffer (TS BufferSource-safe)
  - PDF.js text extract; per-page normalize then join with "\n\n"
  - PageMap + OffsetMap (gap-free coverage); pageLength = end - start
  - Updated manifest's Betriebskosten quote to one PDF.js extracts cleanly
- T04 src/anchor/selectors/{create,resolve}.ts + 25 unit + 7 fixture tests
  - createSelectors emits the maximal redundant set (TextQuote +
    TextPosition + PdfRect + PdfPageText when available)
  - resolveSelectors implements the SharedContracts §7 ladder; confidence
    1.0 (pos+quote) → 0.7 (rect-only) → 0 (unresolved)
  - Cross-module integration test moved to tests/integration/ to honor
    the anchor↛source boundary lint rule
- T05 engine: sync event bus over the closed §4 vocabulary, Map-backed
  repos, services, createEngine() composition root, 12 tests
- T06 work + app: three-pane shell (CollectionList | ViewerShell |
  EvidenceSidebar) wired through EngineProvider; EngineContext lives in
  src/work/ to respect the work↛app boundary; SpikeApp deleted
- T07 AnnotationToolbar: pendingSelection in context; Save runs
  createSelectors → engine.annotations.create → engine.evidence.create
- T08 click-to-reopen + localStorage persistence
  - scrollToAnnotation state in context with a version counter so a
    second click on the same item re-fires the viewer scroll
  - captureSnapshot/restoreSnapshot/attachPersister/restoreFromStorage;
    restore bypasses services to avoid event-loops
  - active-document id persisted alongside the snapshot so reload lands
    on the same fixture; ADR-0005 written
  - 9 persistence tests
- T09 tests/integration/app-prd-scenario.dom.test.tsx
  - end-to-end happy-dom test of PRD scenario steps 1-8 through the real
    React tree; viewer + ingest mocked per ADR-0004's headless-Chromium
    limitation. Fixed memo-deps bug in EvidenceSidebar/ViewerShell where
    useEngineEventTick values were not included in the useMemo deps,
    leaving stale memoization across event-driven re-renders
- vitest.config.ts: happy-dom for *.dom.test.{ts,tsx} files
- noEmit added to tsconfig so tsc -b doesn't litter src/ with .js outputs

Gates: typecheck ✓ lint ✓ test 109/109 across 11 files ✓ build ✓

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/work/ViewerShell.tsx

@@ -0,0 +1,94 @@
+/**
+ * ViewerShell — the centre pane.
+ *
+ * Hosts the viewer adapter (currently the T02 PDF spike) and shows whatever
+ * is active. `work/` consumes only the adapter's public surface
+ * (`PdfSpikeViewer`) — it never touches PDF.js or react-pdf-highlighter-plus
+ * directly. When the PDF library is swapped (or the spike is replaced),
+ * only the adapter module changes; this shell stays the same.
+ *
+ * T06 scope: load + render the active PDF + show stored annotations. The
+ * selection-capture → annotation pipeline is wired in T07; the
+ * click-to-reopen pipeline is wired in T08.
+ */
+
+import { useMemo } from "react";
+import { PdfSpikeViewer, type StoredAnnotation } from "@anchor/index";
+import {
+  useActiveDocument,
+  useEngine,
+  useEngineEventTick,
+  usePendingSelection,
+  useScrollToAnnotation,
+} from "./EngineContext";
+import { AnnotationToolbar } from "./AnnotationToolbar";
+
+export function ViewerShell() {
+  const engine = useEngine();
+  const { document, representation } = useActiveDocument();
+  const { set: setPending } = usePendingSelection();
+  const { id: scrollToId, version: scrollVersion } = useScrollToAnnotation();
+
+  // The viewer needs to re-fetch its highlight list whenever annotations
+  // change. The tick is included in the memo deps so the list re-resolves.
+  const annotationTick = useEngineEventTick("AnnotationCreated");
+
+  const annotations = useMemo<StoredAnnotation[]>(() => {
+    if (!document) return [];
+    return engine.annotations.listByDocument(document.id).map((a) => ({
+      id: a.id,
+      text: a.quote ?? "",
+      selectors: a.selectors,
+    }));
+  }, [document, engine, annotationTick]);
+
+  const fileUrl = useMemo(() => {
+    if (!document) return null;
+    const titleOrId = document.title ?? document.id;
+    return `/fixtures/pdfs/${encodeURIComponent(titleOrId)}`;
+  }, [document]);
+
+  if (!document || !representation || !fileUrl) {
+    return (
+      <main
+        style={{
+          flex: 1,
+          display: "flex",
+          alignItems: "center",
+          justifyContent: "center",
+          color: "#666",
+          fontFamily: "system-ui, sans-serif",
+        }}
+      >
+        Pick a fixture on the left to begin.
+      </main>
+    );
+  }
+
+  return (
+    <main
+      style={{
+        flex: 1,
+        display: "flex",
+        flexDirection: "column",
+        overflow: "hidden",
+        position: "relative",
+      }}
+    >
+      <AnnotationToolbar />
+      <div style={{ flex: 1, overflow: "hidden", position: "relative" }}>
+        <PdfSpikeViewer
+          // Re-key on scrollVersion so clicking the same item twice still
+          // triggers the viewer's mount-time scroll effect.
+          key={`${document.id}#${scrollVersion}`}
+          pdfUrl={fileUrl}
+          storedAnnotations={annotations}
+          {...(scrollToId ? { scrollToAnnotationId: scrollToId } : {})}
+          onSelectionCaptured={(capture, selectors) => {
+            setPending({ capture, selectors });
+          }}
+        />
+      </div>
+    </main>
+  );
+}