Issue #4: Save As Replaces Files Instead of Creating Copies

[tjayrush]

Priority: CRITICAL
Component: File Operations

Description:
File → Save As incorrectly replaces the current project file instead of creating a copy, violating standard Save As behavior.

Steps to Reproduce:

1. Create and save a project
2. Go to File → Save As
3. Enter new filename
4. Save

Expected Behavior:

• Original project file remains unchanged
• New copy created with new filename
• Both projects appear in Open Projects list
• New copy becomes active

Actual Behavior:

• Original project file is replaced/renamed
• Only one project remains open
• Project identity changes instead of creating copy

Impact: Users cannot create project templates or backup copies using standard Save As workflow.