docs: update CLAUDE.md with multitenancy architecture

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

CLAUDE.md

@@ -38,6 +38,7 @@ java -jar cameleer3-server-app/target/cameleer3-server-app-1.0-SNAPSHOT.jar
 - Jackson `JavaTimeModule` for `Instant` deserialization
 - Communication: receives HTTP POST data from agents (executions, diagrams, metrics, logs), serves SSE event streams for config push/commands (config-update, deep-trace, replay, route-control)
 - Maintains agent instance registry (in-memory) with states: LIVE → STALE → DEAD. Auto-heals from JWT claims + heartbeat capabilities on heartbeat/SSE after server restart. Capabilities are updated on every heartbeat (protocol v2). Route catalog falls back to ClickHouse stats for route discovery when registry has incomplete data.
+- Multi-tenancy: each server instance serves one tenant (configured via `CAMELEER_TENANT_ID`, default: `"default"`). Environments (dev/staging/prod) are first-class — agents send `environmentId` at registration. PostgreSQL isolated via schema-per-tenant (`?currentSchema=tenant_{id}`). ClickHouse shared DB with `tenant_id` + `environment` columns, partitioned by `(tenant_id, toYYYYMM(timestamp))`.
 - 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 (key derived deterministically from JWT secret via HMAC-SHA256), bootstrap token for registration