feat: add application log ingestion with OpenSearch storage

Agents can now send application log entries in batches via POST /api/v1/data/logs.
Logs are indexed directly into OpenSearch daily indices (logs-{yyyy-MM-dd}) using
the bulk API. Index template defines explicit mappings for full-text search readiness.

New DTOs (LogEntry, LogBatch) added to cameleer3-common in the agent repo.

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

CLAUDE.md

@@ -36,9 +36,9 @@ java -jar cameleer3-server-app/target/cameleer3-server-app-1.0-SNAPSHOT.jar
 - Spring Boot 3.4.3 parent POM
 - Depends on `com.cameleer3:cameleer3-common` from Gitea Maven registry
 - Jackson `JavaTimeModule` for `Instant` deserialization
-- Communication: receives HTTP POST data from agents, serves SSE event streams for config push/commands
+- Communication: receives HTTP POST data from agents (executions, diagrams, metrics, logs), serves SSE event streams for config push/commands
 - Maintains agent instance registry with states: LIVE → STALE → DEAD
-- Storage: PostgreSQL (TimescaleDB) for structured data, OpenSearch for full-text search
+- Storage: PostgreSQL (TimescaleDB) for structured data, OpenSearch for full-text search and application log storage
 - Security: JWT auth with RBAC (AGENT/VIEWER/OPERATOR/ADMIN roles), Ed25519 config signing, 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`