test(01-03): add integration tests for health, OpenAPI, protocol version, forward compat, and TTL

- HealthControllerIT: health returns 200, no protocol header needed, TTL verified
- OpenApiIT: api-docs returns OpenAPI spec, swagger UI accessible
- ProtocolVersionIT: missing/wrong header returns 400, correct header passes, excluded paths work
- ForwardCompatIT: unknown JSON fields do not cause deserialization errors
- Fix testcontainers version to 2.0.3 (docker-java 3.7.0 for Docker Desktop 29.x compat)
- Fix ClickHouse schema: TTL with toDateTime() cast, non-nullable error columns for tokenbf_v1

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

clickhouse/init/01-schema.sql

@@ -11,8 +11,8 @@ CREATE TABLE IF NOT EXISTS route_executions (
     duration_ms      UInt64,
     correlation_id   String,
     exchange_id      String,
-    error_message    Nullable(String),
-    error_stacktrace Nullable(String),
+    error_message    String DEFAULT '',
+    error_stacktrace String DEFAULT '',
     -- Nested processor executions stored as parallel arrays
     processor_ids       Array(String),
     processor_types     Array(LowCardinality(String)),
@@ -29,7 +29,7 @@ CREATE TABLE IF NOT EXISTS route_executions (
 ENGINE = MergeTree()
 PARTITION BY toYYYYMMDD(start_time)
 ORDER BY (agent_id, status, start_time, execution_id)
-TTL start_time + INTERVAL 30 DAY
+TTL toDateTime(start_time) + toIntervalDay(30)
 SETTINGS ttl_only_drop_parts = 1;
 
 CREATE TABLE IF NOT EXISTS route_diagrams (
@@ -53,5 +53,5 @@ CREATE TABLE IF NOT EXISTS agent_metrics (
 ENGINE = MergeTree()
 PARTITION BY toYYYYMMDD(collected_at)
 ORDER BY (agent_id, metric_name, collected_at)
-TTL collected_at + INTERVAL 30 DAY
+TTL toDateTime(collected_at) + toIntervalDay(30)
 SETTINGS ttl_only_drop_parts = 1;