[M8] cargoxx-pkgs as a flake: cargoxx add → string-form dep

Wrapper: fix cache.nixos.org-1 key; drop AppImage; pin publish to mozart/cargoxx-pkgs.

build/CMakeLists.txt

@@ -63,6 +63,7 @@ target_sources(cargoxx
         ../src/manifest/parser.cpp
         ../src/manifest/writer.cpp
         ../src/resolver/brute_scan.cpp
+        ../src/resolver/cargoxx_pkgs_probe.cpp
         ../src/resolver/conan_probe.cpp
         ../src/resolver/discover.cpp
         ../src/resolver/findmodule_scan.cpp
@@ -201,6 +202,15 @@ target_link_libraries(test_cmd_new PRIVATE
     Catch2::Catch2WithMain
 )
 catch_discover_tests(test_cmd_new)
+add_executable(test_cmd_publish_validation ../tests/cmd_publish_validation.cpp)
+target_link_libraries(test_cmd_publish_validation PRIVATE
+    cargoxx
+    reproc
+    SQLite::SQLite3
+    Catch2::Catch2
+    Catch2::Catch2WithMain
+)
+catch_discover_tests(test_cmd_publish_validation)
 add_executable(test_cmd_remove ../tests/cmd_remove.cpp)
 target_link_libraries(test_cmd_remove PRIVATE
     cargoxx