fix: WinDbg plugin dynamic dbgeng loading, editor two-tone bg, UI polish

WinDbg plugin: load dbgeng.dll dynamically from Debugging Tools directory
instead of static linking (system dbgeng.dll lacks remote DebugConnect).
Copy tools dbghelp.dll next to exe so it loads before System32 version.
Add COM init on DbgEng thread, browse for tools dir, styled dialog.

Editor: derive darker background via theme.background.darker(115) for
visual depth between chrome and editor surfaces.

UI: global scrollbar styling, workspace accent bar 1px, pane tab font
from editor settings, workspace dock default width 128px.

CMakeLists.txt

@@ -151,6 +151,26 @@ target_link_libraries(Reclass PRIVATE
 )
 if(WIN32)
     target_link_libraries(Reclass PRIVATE dbghelp dwmapi psapi raw_pdb)
+
+    # Copy Debugging Tools dbghelp.dll next to Reclass.exe so the Windows
+    # loader picks it up (app dir > System32).  The system dbghelp.dll
+    # lacks StackWalk2 which the tools dbgeng.dll needs for remote debug.
+    set(_DBG_TOOLS_DIRS
+        "C:/Program Files (x86)/Windows Kits/10/Debuggers/x64"
+        "C:/Program Files/Windows Kits/10/Debuggers/x64")
+    foreach(_dir ${_DBG_TOOLS_DIRS})
+        if(EXISTS "${_dir}/dbghelp.dll")
+            foreach(_dll dbghelp.dll dbgcore.dll symsrv.dll)
+                if(EXISTS "${_dir}/${_dll}")
+                    add_custom_command(TARGET Reclass POST_BUILD
+                        COMMAND ${CMAKE_COMMAND} -E copy_if_different
+                            "${_dir}/${_dll}" $<TARGET_FILE_DIR:Reclass>
+                        COMMENT "Copying ${_dll} from Debugging Tools")
+                endif()
+            endforeach()
+            break()
+        endif()
+    endforeach()
 endif()
 
 add_executable(ReclassMcpBridge tools/rcx-mcp-stdio.cpp)