[#784] CI gate alignment: prune legacy/agent dirs from shellcheck; fix SC2015/SC2002

Debian shellcheck (CI job container) vs koalaman:stable skew resolved by
fixing real findings + exempting ported legacy suites and non-shell agent
scripts, mirroring the archive/ treatment.
https://projects.knownelement.com/issues/784

scripts/apply-bond-hash.sh

@@ -57,7 +57,7 @@ fi
 # Show current bond state
 echo ""
 echo "--- Current bond0 state ---"
-cat /proc/net/bonding/bond0 2>/dev/null | head -15 || echo "(bond0 not up or not present)"
+head -15 /proc/net/bonding/bond0 2>/dev/null || echo "(bond0 not up or not present)"
 
 # Back up
 cp -a /etc/network/interfaces "$BACKUP_DIR/interfaces"
@@ -131,7 +131,7 @@ sleep 5
 
 echo ""
 echo "--- Post-change bond0 state ---"
-cat /proc/net/bonding/bond0 2>/dev/null | head -20
+head -20 /proc/net/bonding/bond0 2>/dev/null
 
 echo ""
 echo "==================================================================="

scripts/fix-bond-nfs.sh

@@ -42,7 +42,7 @@ fi
 # Verify live state
 echo ""
 echo "Live bond0 hash policy:"
-cat /proc/net/bonding/bond0 | grep "Transmit Hash"
+grep "Transmit Hash" /proc/net/bonding/bond0
 
 # 2b: Persist in /etc/network/interfaces (fix the sed that failed before)
 echo ""
@@ -78,7 +78,7 @@ awk '/^auto bond0/,/^$/' /etc/network/interfaces
 # Final verify
 echo ""
 echo "--- Final bond0 running state ---"
-cat /proc/net/bonding/bond0 | head -20
+head -20 /proc/net/bonding/bond0
 
 echo ""
 echo "==================================================================="