feat(tools): concurrent read-only tool execution with batch partitioning

.env.example

@@ -181,6 +181,10 @@ AGENT_STUCK_THRESHOLD_SECS=300
 # AGENT_MAX_TOKENS_PER_JOB=0
 # Enable planning phase before tool execution (default: true)
 AGENT_USE_PLANNING=true
+# Maximum concurrent tool executions per LLM turn (default: 10, clamped to [1, 100]).
+# Keep <= DB pool size / 2 to avoid connection exhaustion when concurrent
+# tools are DB-heavy (memory_search, job_status, etc.).
+# AGENT_MAX_CONCURRENT_TOOLS=10
 
 # Self-repair settings
 SELF_REPAIR_CHECK_INTERVAL_SECS=60