🐛 fix(symbol): index all system tsf files

Do not drop system-library .tsf units when the file stem differs from top-level symbols.

Add test_provider support for --interpreter=... and an interpreter integration test that validates full indexing plus completion+resolve snippet.

lsp-server/test/test_provider/test_main.cppm

@@ -7,6 +7,7 @@ import std;
 import lsp.test.framework;
 import lsp.test.provider.completion;
 import lsp.test.provider.definitions;
+import lsp.test.provider.interpreter;
 import lsp.test.provider.json_flow;
 import lsp.test.provider.json_provider_coverage;
 import lsp.test.provider.misc;
@@ -22,10 +23,18 @@ export int Run(int argc, char** argv)
 
     for (int i = 1; i < argc; ++i)
     {
-        if (std::string_view(argv[i]) == "--exit-provider")
+        std::string_view arg(argv[i]);
+
+        if (arg == "--exit-provider")
         {
             return lsp::test::provider::RunExitProviderChild();
         }
+
+        constexpr std::string_view kInterpreterPrefix = "--interpreter=";
+        if (arg.starts_with(kInterpreterPrefix))
+        {
+            lsp::test::provider::SetInterpreterPath(std::string(arg.substr(kInterpreterPrefix.size())));
+        }
     }
 
     lsp::test::TestRunner runner;
@@ -40,6 +49,8 @@ export int Run(int argc, char** argv)
     lsp::test::provider::CompletionTests::Register(runner);
     std::cout << "  - Definition tests" << std::endl;
     lsp::test::provider::DefinitionTests::Register(runner);
+    std::cout << "  - Interpreter tests" << std::endl;
+    lsp::test::provider::InterpreterTests::Register(runner);
     std::cout << "  - JSON flow tests" << std::endl;
     lsp::test::provider::JsonFlowTests::Register(runner);
     std::cout << "  - JSON provider coverage tests" << std::endl;