chore: remove kanban_cpp app

Gitea repo dataforge/kanban_cpp archived (read-only).
Local apps/kanban_cpp/ deleted, CMake subdir registration removed.
registry.db entry + pc_locations row purged (regenerable via fn index +
manual delete since indexer upserts but does not purge orphaned apps).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

cpp/CMakeLists.txt

@@ -529,9 +529,3 @@ set(_PROCESS_EXPLORER_DIR ${CMAKE_SOURCE_DIR}/../apps/process_explorer)
 if(EXISTS ${_PROCESS_EXPLORER_DIR}/CMakeLists.txt)
     add_subdirectory(${_PROCESS_EXPLORER_DIR} ${CMAKE_BINARY_DIR}/apps/process_explorer)
 endif()
-
-# --- kanban_cpp (lives in apps/, issue 0096) ---
-set(_KANBAN_CPP_DIR ${CMAKE_SOURCE_DIR}/../apps/kanban_cpp)
-if(EXISTS ${_KANBAN_CPP_DIR}/CMakeLists.txt)
-    add_subdirectory(${_KANBAN_CPP_DIR} ${CMAKE_BINARY_DIR}/apps/kanban_cpp)
-endif()