Migrate analytics from SQLite to ClickHouse

SQLite was too slow for analytical aggregations on traffic_events and
waf_events (millions of rows, GROUP BY, COUNT DISTINCT). ClickHouse is
a columnar OLAP database purpose-built for this workload.

- Add ClickHouse container to Docker Compose with health check
- Create src/lib/clickhouse/client.ts with singleton client, table DDL,
  insert helpers, and all analytics query functions
- Update log-parser.ts and waf-log-parser.ts to write to ClickHouse
- Remove purgeOldEntries — ClickHouse TTL handles 90-day retention
- Rewrite analytics-db.ts and waf-events.ts to query ClickHouse
- Remove trafficEvents/wafEvents from SQLite schema, add migration
- CLICKHOUSE_PASSWORD is required (no hardcoded default)
- Update .env.example, README, and test infrastructure

API response shapes are unchanged — no frontend modifications needed.
Parse state (file offsets) remains in SQLite.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

package-lock.json

@@ -8,6 +8,7 @@
       "name": "caddy-proxy-manager",
       "version": "1.0.0",
       "dependencies": {
+        "@clickhouse/client": "^1.18.2",
         "@radix-ui/react-accordion": "^1.2.12",
         "@radix-ui/react-avatar": "^1.1.11",
         "@radix-ui/react-checkbox": "^1.3.3",
@@ -579,6 +580,24 @@
         "node": ">=6.9.0"
       }
     },
+    "node_modules/@clickhouse/client": {
+      "version": "1.18.2",
+      "resolved": "https://registry.npmjs.org/@clickhouse/client/-/client-1.18.2.tgz",
+      "integrity": "sha512-fuquQswRSHWM6D079ZeuGqkMOsqtcUPL06UdTnowmoeeYjVrqisfVmvnw8pc3OeKS4kVb91oygb/MfLDiMs0TQ==",
+      "license": "Apache-2.0",
+      "dependencies": {
+        "@clickhouse/client-common": "1.18.2"
+      },
+      "engines": {
+        "node": ">=16"
+      }
+    },
+    "node_modules/@clickhouse/client-common": {
+      "version": "1.18.2",
+      "resolved": "https://registry.npmjs.org/@clickhouse/client-common/-/client-common-1.18.2.tgz",
+      "integrity": "sha512-J0SG6q9V31ydxonglpj9xhNRsUxCsF71iEZ784yldqMYwsHixj/9xHFDgBDX3DuMiDx/kPDfXnf+pimp08wIBA==",
+      "license": "Apache-2.0"
+    },
     "node_modules/@date-fns/tz": {
       "version": "1.4.1",
       "resolved": "https://registry.npmjs.org/@date-fns/tz/-/tz-1.4.1.tgz",