feat: natural language query + production hardening

Features:
- Add /api/ask endpoint for plain-language audit log queries
- Regex-based time/entity extraction (no LLM required for parsing)
- LLM-powered narrative summarisation with OpenAI-compatible APIs
- Graceful fallback to structured bullet lists when LLM is unavailable
- Frontend ask panel with markdown rendering and cited events

Production:
- Harden Dockerfile: non-root user, gunicorn+uvicorn workers
- Add docker-compose.prod.yml with internal networks and health checks
- Add nginx reverse proxy with security headers
- MongoDB no longer exposed externally in production

Tests:
- 29 new tests for ask parsing, query building, and endpoint behaviour
- Fix conftest monkeypatch for routes.ask events collection

Bump version to 1.1.0

backend/frontend/style.css

@@ -377,6 +377,84 @@ input {
   margin: 0;
 }
 
+/* Ask / Natural Language Query */
+.ask-form {
+  margin-top: 10px;
+}
+
+.ask-row {
+  display: flex;
+  gap: 10px;
+  align-items: center;
+}
+
+.ask-input {
+  flex: 1;
+  padding: 12px 14px;
+  border-radius: 10px;
+  border: 1px solid var(--border);
+  background: rgba(255, 255, 255, 0.02);
+  color: var(--text);
+  font-size: 15px;
+}
+
+.ask-result {
+  margin-top: 16px;
+}
+
+.ask-answer {
+  background: rgba(125, 211, 252, 0.06);
+  border: 1px solid rgba(125, 211, 252, 0.2);
+  border-radius: 12px;
+  padding: 16px;
+  line-height: 1.55;
+  margin-bottom: 14px;
+}
+
+.ask-answer code {
+  background: rgba(255,255,255,0.06);
+  padding: 2px 6px;
+  border-radius: 6px;
+  font-size: 13px;
+}
+
+.ask-events {
+  margin-bottom: 14px;
+}
+
+.ask-events h4 {
+  margin: 0 0 10px;
+  color: var(--muted);
+  font-size: 14px;
+  text-transform: uppercase;
+  letter-spacing: 0.06em;
+}
+
+.event--compact {
+  padding: 12px;
+  margin-bottom: 10px;
+}
+
+.event--compact h3 {
+  font-size: 15px;
+}
+
+.source-health {
+  display: grid;
+  grid-template-columns: repeat(auto-fit, minmax(min(200px, 100%), 1fr));
+  gap: 10px;
+}
+
+.health-card {
+  border: 1px solid var(--border);
+  border-radius: 10px;
+  padding: 10px 12px;
+  background: rgba(255, 255, 255, 0.02);
+  display: flex;
+  flex-direction: column;
+  gap: 4px;
+}
+
 @media (max-width: 640px) {
   .hero {
     flex-direction: column;
@@ -386,4 +464,9 @@ input {
     flex-direction: column;
     align-items: stretch;
   }
+
+  .ask-row {
+    flex-direction: column;
+    align-items: stretch;
+  }
 }