feat(01-03): add test infrastructure, protocol version interceptor, and app bootstrap

- AbstractClickHouseIT base class with Testcontainers ClickHouse and schema init
- ProtocolVersionInterceptor validates X-Cameleer-Protocol-Version:1 on data/agent paths
- WebConfig registers interceptor with path patterns, excludes health/docs
- Cameleer3ServerApplication with @EnableScheduling and component scanning
- application-test.yml with small buffer config for tests

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

cameleer3-server-app/src/test/resources/application-test.yml

@@ -0,0 +1,11 @@
+spring:
+  datasource:
+    url: jdbc:ch://placeholder:8123/cameleer3
+    username: default
+    password: ""
+    driver-class-name: com.clickhouse.jdbc.ClickHouseDriver
+
+ingestion:
+  buffer-capacity: 100
+  batch-size: 10
+  flush-interval-ms: 100