fix: extract snapshot data from chunks, reduce ClickHouse log noise

- ChunkAccumulator now extracts inputBody/outputBody/inputHeaders/outputHeaders
  from ExecutionChunk.inputSnapshot/outputSnapshot instead of storing empty strings
- Set ClickHouse server log level to warning (was trace by default)
- Update CLAUDE.md to document Ed25519 key derivation

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

CLAUDE.md

@@ -40,7 +40,7 @@ java -jar cameleer3-server-app/target/cameleer3-server-app-1.0-SNAPSHOT.jar
 - Maintains agent instance registry (in-memory) with states: LIVE → STALE → DEAD. Auto-heals from JWT claims on heartbeat/SSE after server restart. Route catalog falls back to ClickHouse stats for route discovery when registry has incomplete data.
 - Storage: PostgreSQL for RBAC, config, and audit; ClickHouse for all observability data (executions, search, logs, metrics, stats, diagrams). ClickHouse schema migrations in `clickhouse/*.sql`, run idempotently on startup by `ClickHouseSchemaInitializer`. Use `IF NOT EXISTS` for CREATE and ADD PROJECTION.
 - Logging: ClickHouse JDBC set to INFO (`com.clickhouse`), HTTP client to WARN (`org.apache.hc.client5`) in application.yml
-- Security: JWT auth with RBAC (AGENT/VIEWER/OPERATOR/ADMIN roles), Ed25519 config signing, bootstrap token for registration
+- Security: JWT auth with RBAC (AGENT/VIEWER/OPERATOR/ADMIN roles), Ed25519 config signing (key derived deterministically from JWT secret via HMAC-SHA256), bootstrap token for registration
 - OIDC: Optional external identity provider support (token exchange pattern). Configured via admin API, stored in database (`server_config` table)
 - User persistence: PostgreSQL `users` table, admin CRUD at `/api/v1/admin/users`
 - Usage analytics: ClickHouse `usage_events` table tracks authenticated UI requests, flushed every 5s