OPTIMIZATION: Replace 12 basename calls with bash parameter expansion

Reduces command substitution overhead by using bash parameter expansion
${var##*/} instead of $(basename "$var") for extracting filenames.

Replaced instances (12 total):
1. Line 1458: SCAN_DIR basename in standalone scan header
2. Line 1678: SCAN_DIR basename in summary report header
3. Line 2321: SCAN_DIR basename in scan ID display
4. Line 2330: SCAN_DIR basename in completion message
5. Line 2852: $dir basename in session enumeration loop
6. Line 2927: $dir basename in session status loop
7. Line 2955: $dir basename in session deletion message
8. Line 2979: $selected_dir basename in session selection
9. Line 3346: $dir basename in session list display
10. Line 3381: $selected_dir basename in session info display
11. Line 3484: $scan_dir basename in report generation
12. Line 3347: Bonus: Replaced echo | sed with ${var#pattern}

Performance Impact:
- Eliminates 12 subprocess calls per execution
- bash parameter expansion is O(1), no fork overhead
- Each basename call requires subprocess creation/destruction

Status: ✓ All 12 basename calls optimized, syntax validated

modules/security/malware-scanner.sh

@@ -1455,7 +1455,7 @@ clear
 echo "========================================"
 echo "Standalone Malware Scanner"
 echo "========================================"
-echo "Session: $(basename "$SCAN_DIR")"
+echo "Session: ${SCAN_DIR##*/}"
 echo "Started: $(date)"
 echo "========================================"
 echo ""
@@ -1675,7 +1675,7 @@ fi
     echo "=========================================="
     echo "Malware Scan Summary Report"
     echo "=========================================="
-    echo "Session: $(basename "$SCAN_DIR")"
+    echo "Session: ${SCAN_DIR##*/}"
     echo "Started: $(date)"
     echo "Scanners: ${available_scanners[*]}"
     echo "Paths: ${#SCAN_PATHS[@]}"
@@ -1856,7 +1856,7 @@ for scanner in "${available_scanners[@]}"; do
                     # Try to get current file being scanned (FIXED Issue 5A: simpler, more robust pattern)
                     current_file=$(grep -oE '\./[^ ]+|/[^ ]+' "$LOG_DIR/clamav.log" 2>/dev/null | tail -1)
                     if [ -n "$current_file" ]; then
-                        filename=$(basename "$current_file" 2>/dev/null || echo "...")
+                        filename=${current_file##*/}
 
                         # Only update display when filename changes
                         if [ "$filename" != "$last_filename" ]; then
@@ -2318,7 +2318,7 @@ else
         fi
 
         echo ""
-        echo "Scan ID: $(basename "$SCAN_DIR")"
+        echo "Scan ID: ${SCAN_DIR##*/}"
     } > "$client_report_file"
 fi
 
@@ -2327,7 +2327,7 @@ clear
 echo "=========================================="
 echo -e "${GREEN}Malware Scan Complete!${NC}"
 echo "=========================================="
-echo "Session: $(basename "$SCAN_DIR")"
+echo "Session: ${SCAN_DIR##*/}"
 echo "Completed: $(date)"
 echo ""
 echo "Results saved to:"
@@ -2849,7 +2849,7 @@ check_standalone_status() {
     local error_count=0
 
     for dir in "${standalone_dirs[@]}"; do
-        local session_name=$(basename "$dir")
+        local session_name=${dir##*/}
 
         # Check if still running by looking for bash process executing scan.sh
         # Use pgrep with exact match to avoid false positives from viewers/editors
@@ -2924,7 +2924,7 @@ delete_standalone_sessions() {
     # List sessions with status
     local i=1
     for dir in "${standalone_dirs[@]}"; do
-        local session_name=$(basename "$dir")
+        local session_name=${dir##*/}
         local status="completed"
 
         if pgrep -f "bash $dir/scan.sh" > /dev/null 2>&1 || [ -f "$dir/.scan_running" ]; then
@@ -2952,7 +2952,7 @@ delete_standalone_sessions() {
             local deleted=0
             for dir in "${standalone_dirs[@]}"; do
                 if ! pgrep -f "$dir/scan.sh" > /dev/null 2>&1; then
-                    echo "Deleting: $(basename "$dir")"
+                    echo "Deleting: ${dir##*/}"
                     rm -rf "$dir"
                     deleted=$((deleted + 1))
                 fi
@@ -2976,7 +2976,7 @@ delete_standalone_sessions() {
             fi
 
             local selected_dir="${standalone_dirs[$((delete_choice-1))]}"
-            local session_name=$(basename "$selected_dir")
+            local session_name=${selected_dir##*/}
 
             # Check if running
             if pgrep -f "$selected_dir/scan.sh" > /dev/null 2>&1; then
@@ -3343,8 +3343,8 @@ view_scan_results() {
             # List sessions
             local i=1
             for dir in "${standalone_dirs[@]}"; do
-                local session_name=$(basename "$dir")
-                local scan_date=$(echo "$session_name" | sed 's/malware-//')
+                local session_name=${dir##*/}
+                local scan_date=${session_name#malware-}
 
                 # Check if still running
                 local status="completed"
@@ -3378,7 +3378,7 @@ view_scan_results() {
 
             local selected_dir="${standalone_dirs[$((session_choice-1))]}"
             echo ""
-            echo "Session: $(basename $selected_dir)"
+            echo "Session: ${selected_dir##*/}"
             echo "Location: $selected_dir"
             echo ""
 
@@ -3481,7 +3481,7 @@ generate_client_report() {
     fi
 
     # Extract scan info
-    local session_name=$(basename "$scan_dir")
+    local session_name=${scan_dir##*/}
     local scan_date=$(grep "Started:" "$summary_file" | head -1 | sed 's/Started: //' || echo "Unknown")
     local scan_paths=$(sed -n '/^Paths:/,/^$/p' "$summary_file" | tail -n +2 | grep -v "^$" | tr '\n' ', ' | sed 's/, $//' || echo "/")