feat: matrix/graph data views, wire-generated anomalies, http cookie fix

- auth: session cookie Secure only over https — plain-http LAN access was
  silently dropping the cookie, killing WS auth ('connection unstable')
- wire ghost: server-side spike detection on jitter baseline (3σ + 2.5×mean,
  20KB/s floor, 20s throttle) — wire anomalies now flood every session with
  zero hardware, pushed to clients as {type:'anomaly'} frames
- telemetry cadence 3-5s for live graphs; ambient whispers unchanged
- frontend: MATRIX view (data-rain interleaved with live utterances/anomaly/
  telemetry strings), GRAPHS view (scrolling jitter/variance/dns lines +
  anomaly markers + counters), BOARD/MATRIX/GRAPHS switcher
- connection banner: 'connecting' is now neutral 'tuning the veil…', only
  unstable/closed warns
- db: recreated quantumancy(+_test) as UTF8 (was SQL_ASCII — crashed on
  non-ASCII spirit text); README quickstart updated
- i18n: seance.views.* EN/ES

frontend/src/components/MatrixView.css

@@ -0,0 +1,57 @@
+/* MatrixView — "matrix rain" live-data view for the séance board area.
+   Tokens: bg #07070d · phosphor #7cffb2 · violet #b26bff · blood #ff3b5c. */
+
+.matrix-view {
+  position: relative;
+  width: 100%;
+  height: 100%;
+  min-height: 0;
+  background: #07070d;
+  border: 1px solid rgba(124, 255, 178, 0.18);
+  border-radius: 6px;
+  overflow: hidden;
+  filter: drop-shadow(0 0 18px rgba(7, 7, 13, 0.9));
+}
+
+.matrix-view canvas {
+  position: absolute;
+  inset: 0;
+}
+
+.matrix-listening {
+  position: absolute;
+  left: 14px;
+  bottom: 12px;
+  margin: 0;
+  color: #b26bff;
+  font-family: 'IBM Plex Mono', ui-monospace, Menlo, monospace;
+  font-size: 0.78rem;
+  letter-spacing: 0.22em;
+  text-transform: uppercase;
+  text-shadow: 0 0 12px rgba(178, 107, 255, 0.7);
+  pointer-events: none;
+}
+
+/* ---------- view switcher (BOARD / MATRIX / GRAPHS) ----------
+   Styles live here because SeancePage.css is outside this change's scope;
+   the tab buttons themselves reuse the existing .mode-tab look. */
+
+.seance-view-tabs {
+  position: absolute;
+  top: 8px;
+  left: 50%;
+  transform: translateX(-50%);
+  z-index: 6;
+  display: flex;
+  gap: 4px;
+  padding: 2px;
+  background: rgba(16, 16, 26, 0.85);
+  border: 1px solid rgba(124, 255, 178, 0.18);
+  border-radius: 5px;
+  backdrop-filter: blur(3px);
+}
+
+.seance-view-tabs .mode-tab {
+  font-size: 0.7rem;
+  padding: 0.3rem 0.6rem;
+}