feat: simplify cmd bar keyword, add File menu class/struct/enum, remove Align Members

- Command bar shows static keyword (struct/class/enum) without dropdown or colon
- Right-click keyword in cmd bar for class↔struct conversion (enum blocked)
- File menu: New Class (Ctrl+N), New Struct (Ctrl+T), New Enum (Ctrl+E)
- Project explorer right-click: New Class/Struct/Enum on Project node
- Explorer right-click: Convert to Class/Struct on class/struct items
- Remove Align Members submenu, performRealignment, computeStructAlignment
- Remove screenshot code and screenshot.png

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

CMakeLists.txt

@@ -116,14 +116,6 @@ endforeach()
 
 include(deploy)
 
-if(TARGET deploy)
-    add_custom_target(screenshot ALL
-        COMMAND Reclass --screenshot ${CMAKE_BINARY_DIR}/screenshot.png
-        DEPENDS Reclass deploy
-        WORKING_DIRECTORY ${CMAKE_BINARY_DIR}
-        COMMENT "Capturing UI screenshot with class open..."
-    )
-endif()
 
 set(_combine_script "${CMAKE_BINARY_DIR}/combine_sources.cmake")
 file(WRITE ${_combine_script} "