Merge branch 'origin/master' - combine double-execution fixes

Both branches fixed the --exec double-execution bug with complementary approaches:
- origin/master: Added executeStartupScripts() method for cleaner separation
- HEAD: Avoided engine recreation to preserve state

This merge keeps the best of both: executeStartupScripts() called on the
existing engine without recreation.

Also accepts deletion of flaky test_viewport_visual.py from origin/master.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

tests/unit/test_viewport_visual.py

@@ -1,141 +0,0 @@
-#!/usr/bin/env python3
-"""Visual viewport test with screenshots"""
-
-import mcrfpy
-from mcrfpy import Window, Frame, Caption, Color
-import sys
-
-def test_viewport_visual(runtime):
-    """Visual test of viewport modes"""
-    mcrfpy.delTimer("test")
-    
-    print("Creating visual viewport test...")
-    
-    # Get window singleton
-    window = Window.get()
-    
-    # Create test scene
-    scene = mcrfpy.sceneUI("test")
-    
-    # Create visual elements at game resolution boundaries
-    game_res = window.game_resolution
-    
-    # Full boundary frame
-    boundary = Frame(pos=(0, 0), size=(game_res[0], game_res[1]),
-                    fill_color=Color(40, 40, 80),
-                    outline_color=Color(255, 255, 0),
-                    outline=3)
-    scene.append(boundary)
-    
-    # Corner markers
-    corner_size = 100
-    colors = [
-        Color(255, 100, 100),  # Red TL
-        Color(100, 255, 100),  # Green TR
-        Color(100, 100, 255),  # Blue BL
-        Color(255, 255, 100),  # Yellow BR
-    ]
-    positions = [
-        (0, 0),  # Top-left
-        (game_res[0] - corner_size, 0),  # Top-right
-        (0, game_res[1] - corner_size),  # Bottom-left
-        (game_res[0] - corner_size, game_res[1] - corner_size)  # Bottom-right
-    ]
-    labels = ["TL", "TR", "BL", "BR"]
-    
-    for (x, y), color, label in zip(positions, colors, labels):
-        corner = Frame(pos=(x, y), size=(corner_size, corner_size),
-                      fill_color=color,
-                      outline_color=Color(255, 255, 255),
-                      outline=2)
-        scene.append(corner)
-        
-        text = Caption(text=label, pos=(x + 10, y + 10))
-        text.font_size = 32
-        text.fill_color = Color(0, 0, 0)
-        scene.append(text)
-    
-    # Center crosshair
-    center_x = game_res[0] // 2
-    center_y = game_res[1] // 2
-    h_line = Frame(pos=(0, center_y - 1), size=(game_res[0], 2),
-                  fill_color=Color(255, 255, 255, 128))
-    v_line = Frame(pos=(center_x - 1, 0), size=(2, game_res[1]),
-                  fill_color=Color(255, 255, 255, 128))
-    scene.append(h_line)
-    scene.append(v_line)
-    
-    # Mode text
-    mode_text = Caption(text=f"Mode: {window.scaling_mode}",
-                       pos=(center_x - 100, center_y - 50))
-    mode_text.font_size = 36
-    mode_text.fill_color = Color(255, 255, 255)
-    scene.append(mode_text)
-
-    # Resolution text
-    res_text = Caption(text=f"Game: {game_res[0]}x{game_res[1]}",
-                      pos=(center_x - 150, center_y + 10))
-    res_text.font_size = 24
-    res_text.fill_color = Color(200, 200, 200)
-    scene.append(res_text)
-    
-    from mcrfpy import automation
-    
-    # Test different modes and window sizes
-    def test_sequence(runtime):
-        mcrfpy.delTimer("seq")
-        
-        # Test 1: Fit mode with original size
-        print("Test 1: Fit mode, original window size")
-        automation.screenshot("viewport_01_fit_original.png")
-        
-        # Test 2: Wider window
-        window.resolution = (1400, 768)
-        print(f"Test 2: Fit mode, wider window {window.resolution}")
-        automation.screenshot("viewport_02_fit_wide.png")
-        
-        # Test 3: Taller window  
-        window.resolution = (1024, 900)
-        print(f"Test 3: Fit mode, taller window {window.resolution}")
-        automation.screenshot("viewport_03_fit_tall.png")
-        
-        # Test 4: Center mode
-        window.scaling_mode = "center"
-        mode_text.text = "Mode: center"
-        print(f"Test 4: Center mode {window.resolution}")
-        automation.screenshot("viewport_04_center.png")
-        
-        # Test 5: Stretch mode
-        window.scaling_mode = "stretch"
-        mode_text.text = "Mode: stretch"
-        window.resolution = (1280, 720)
-        print(f"Test 5: Stretch mode {window.resolution}")
-        automation.screenshot("viewport_05_stretch.png")
-        
-        # Test 6: Small window with fit
-        window.scaling_mode = "fit"
-        mode_text.text = "Mode: fit"
-        window.resolution = (640, 480)
-        print(f"Test 6: Fit mode, small window {window.resolution}")
-        automation.screenshot("viewport_06_fit_small.png")
-        
-        print("\nViewport visual test completed!")
-        print("Screenshots saved:")
-        print("  - viewport_01_fit_original.png")
-        print("  - viewport_02_fit_wide.png")
-        print("  - viewport_03_fit_tall.png")
-        print("  - viewport_04_center.png")
-        print("  - viewport_05_stretch.png")
-        print("  - viewport_06_fit_small.png")
-        
-        sys.exit(0)
-    
-    # Start test sequence after a short delay
-    mcrfpy.setTimer("seq", test_sequence, 500)
-
-# Main execution
-print("Starting visual viewport test...")
-mcrfpy.createScene("test")
-mcrfpy.setScene("test")
-mcrfpy.setTimer("test", test_viewport_visual, 100)
-print("Test scheduled...")