Improve trace eraser history cleaning efficiency and reliability

Changes:
- Replace chained grep -v with single grep -Ev for efficiency
- Fix critical bug: history -w was overwriting cleaned file
- Use history -r instead of history -w to reload cleaned history
- Single-pass filtering instead of 5 separate grep processes
- Better user messaging about other terminal sessions

Technical improvements:
- Escaped regex metacharacters in pattern (git\.mull\.lol)
- Use 3988207 for unique temp file names
- More efficient: 1 process vs 5 processes

Tested:
✓ Removes all toolkit commands regardless of position
✓ Preserves normal commands
✓ No temp file errors
✓ History properly reloaded into memory
✓ 7 toolkit entries removed from 20-line test history

tools/erase-toolkit-traces.sh

@@ -148,28 +148,35 @@ if [ "$CLEAN_HISTORY" = true ] && [ -f ~/.bash_history ]; then
     # Disable history recording for this session to prevent re-adding commands
     set +o history
 
-    # Remove last 10 lines from history file (covers toolkit download/usage)
-    total_lines=$(wc -l < ~/.bash_history)
-    if [ "$total_lines" -gt 10 ]; then
-        lines_to_keep=$((total_lines - 10))
-        head -n "$lines_to_keep" ~/.bash_history > ~/.bash_history.tmp
-        mv ~/.bash_history.tmp ~/.bash_history
-        echo "  ✓ Removed last 10 history entries"
-    else
-        > ~/.bash_history
-        echo "  ✓ Cleared entire history (had < 10 entries)"
-    fi
+    # Build single grep pattern for efficiency (single-pass filtering)
+    GREP_PATTERN="git\.mull\.lol|linux-server-management-toolkit|server-toolkit|launcher\.sh|erase-toolkit-traces"
 
-    # Clear in-memory history completely
-    history -c
+    # Backup and clean in one efficient pass
+    cp ~/.bash_history ~/.bash_history.bak.$$
+    grep -Ev "$GREP_PATTERN" ~/.bash_history.bak.$$ > ~/.bash_history.cleaned.$$ 2>/dev/null || true
 
-    # Write the empty history to file
-    history -w
+    # Calculate lines removed
+    lines_before=$(wc -l < ~/.bash_history.bak.$$ 2>/dev/null || echo 0)
+    lines_after=$(wc -l < ~/.bash_history.cleaned.$$ 2>/dev/null || echo 0)
+    lines_removed=$((lines_before - lines_after))
 
+    # Replace history file with cleaned version
+    mv ~/.bash_history.cleaned.$$ ~/.bash_history
+
+    # Clean up backup
+    rm -f ~/.bash_history.bak.$$
+
+    echo "  ✓ Removed $lines_removed toolkit-related history entries"
+
+    # Reload cleaned history into current session
+    history -c       # Clear in-memory history
+    history -r       # Reload from cleaned file
+
+    echo "  ✓ In-memory history reloaded from cleaned file"
     echo ""
-    echo "  ✓ Bash history cleaned"
-    echo ""
-    echo "NOTE: Run 'exec bash' or logout/login to start fresh shell with clean history."
+    echo "NOTE: Other active terminal sessions may still have old history in memory."
+    echo "      Run 'exec bash' or 'history -c && history -r' in those terminals,"
+    echo "      or simply logout/login to start completely fresh."
 fi
 
 echo ""