[M5+] drop curated linkdb JSON; SQLite overlay is the single source

src/linkdb/linkdb.cppm

@@ -22,14 +22,6 @@ struct Recipe {
 
 namespace cargoxx::linkdb::detail {
 
-struct CuratedRecipe {
-    std::string version_range;
-    std::string nixpkgs_attr;
-    std::string find_package;
-    std::vector<std::string> targets;
-    bool components_supported = false;
-};
-
 struct OverlayRow {
     std::string version_range;
     std::string nixpkgs_attr;
@@ -140,7 +132,6 @@ class Database {
 
   private:
     Database() = default;
-    std::map<std::string, std::vector<detail::CuratedRecipe>> curated_;
     std::unique_ptr<detail::OverlayState> overlay_;
 };
 
@@ -150,11 +141,4 @@ class Database {
 //   <cwd>/.cargoxx-linkdb.sqlite             (final fallback)
 auto default_overlay_path() -> std::filesystem::path;
 
-// Pure helpers exported for unit testing.
-auto substitute_components(std::string find_package, const std::vector<std::string>& components)
-    -> std::string;
-
-auto expand_targets(const std::vector<std::string>& templates,
-                    const std::vector<std::string>& components) -> std::vector<std::string>;
-
 } // namespace cargoxx::linkdb