test(script): names, arguments and exit codes, in process and by CLI

RunScript on hand-built configurations: the named script alone runs,
with the project, the project directory and the arguments exactly as
given; its return value comes back whole from 0 to 255 and as 1 outside
that; a script that throws exits 1. A project without scripts, a
duplicate, an untypeable name, a missing callback and an unknown name
all fail without running anything. ctx.Run returns the command's exit
code and 128+signal for a killed one, and ShellQuote carries quotes,
spaces and expansions through sh intact.

Then the same through Run() with a fixture project, because the parsing
is where this goes wrong. `run record a --help -v clean --debug
--version run` must hand all seven words to the script, leave the one
project arg that stood before `run` alone, and not delete the staged
bin/ and build/. `run clean` and `run help` look for scripts of those
names. Moving the two capture branches below the verbs in the parse
loop fails this test.

The command-line half needs the installed module sources and is skipped
without them, but only when the in-process half reported no failure.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

tests/Script/fixture/project.cpp

@@ -0,0 +1,30 @@
+// SPDX-License-Identifier: LGPL-3.0-only
+// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®
+
+import std;
+import Crafter.Build;
+using namespace Crafter;
+
+// Scripts that report what they were handed. The test that loads this file
+// drives the real command line and can only observe a script through its
+// exit code and through what it leaves in the project directory.
+extern "C" Configuration CrafterBuildProject(std::span<const std::string_view> args) {
+    Configuration cfg;
+    cfg.path = "./";
+    cfg.name = "script-fixture";
+    cfg.outputName = "script-fixture";
+    // Applied so that a script argument which leaked into the project's
+    // args would be visible: in cfg.projectArgs, or as cfg.debug.
+    ApplyStandardArgs(cfg, args);
+
+    cfg.scripts.push_back({"record", [](ScriptContext& ctx) {
+        std::ofstream out(ctx.projectDir / "record.txt");
+        for (const std::string& arg : ctx.args) std::println(out, "arg:{}", arg);
+        for (const std::string& arg : ctx.project.projectArgs) std::println(out, "projectArg:{}", arg);
+        std::println(out, "debug:{}", ctx.project.debug);
+        std::println(out, "project:{}", ctx.project.name);
+        return 42;
+    }});
+    cfg.scripts.push_back({"shell", [](ScriptContext& ctx) { return ctx.Run("exit 7"); }});
+    return cfg;
+}