feat: add local config file for user overrides

Add ~/.kugetsu/config file that sources on each command call for
persistent user overrides like MAX_CONCURRENT_AGENTS.

Fixes #67

skills/kugetsu/scripts/kugetsu

@@ -9,8 +9,8 @@ INDEX_FILE="$KUGETSU_DIR/index.json"
 NOTIFICATIONS_FILE="$KUGETSU_DIR/notifications.json"
 LOGS_DIR="$KUGETSU_DIR/logs"
 MAX_CONCURRENT_AGENTS="${MAX_CONCURRENT_AGENTS:-3}"
-AGENT_COUNT_FILE="$KUGETSU_DIR/.agent_count"
+
-AGENT_LOCK_FILE="$KUGETSU_DIR/.agent_lock"
+[ -f "$KUGETSU_DIR/config" ] && source "$KUGETSU_DIR/config"
 
 acquire_agent_slot() {
     local timeout="${1:-300}"