[M5+] add resolver::verify_link + provisional overlay lifecycle

src/resolver/resolver.cppm

@@ -4,6 +4,7 @@ import std;
 import cargoxx.util;
 import cargoxx.exec;
 import cargoxx.linkdb;
+import cargoxx.manifest;
 
 export namespace cargoxx::resolver {
 
@@ -89,4 +90,29 @@ auto parse_vcpkg_usage(std::string_view usage_text)
 // ResolutionUnknownPackage; transport errors → ResolutionNetworkError.
 auto vcpkg_probe(const std::string& name) -> util::Result<VcpkgRecipe>;
 
+// Caller-supplied closure that runs `cargoxx build` (or any equivalent
+// build) on a project rooted at the given path. Injected so the resolver
+// stays decoupled from `cargoxx.cli`.
+using BuildFn =
+    std::function<util::Result<void>(const std::filesystem::path& project_root)>;
+
+struct VerifyLinkRequest {
+    linkdb::Recipe candidate;          // recipe under test
+    std::string source;                // "conan" | "vcpkg" | "nix-probe"
+    std::string package_name;
+    std::string version_spec;          // user-supplied spec (e.g. "*", "1.2")
+    std::vector<std::string> components;
+    std::filesystem::path overlay_path; // sqlite file we read/write
+    std::filesystem::path scratch_root; // parent dir for the tmp project
+};
+
+// Scaffolds a tiny Cargoxx project under `req.scratch_root`, writes a
+// provisional overlay row pointing at `req.candidate`, runs `build_fn` on
+// the project (typically `cli::cmd_build`), and depending on the build
+// result either confirms the provisional row (verified_at = now) or
+// deletes it. Cleans the tmp project regardless. Returns success only
+// when the build itself succeeded.
+auto verify_link(const VerifyLinkRequest& req, const BuildFn& build_fn)
+    -> util::Result<void>;
+
 } // namespace cargoxx::resolver