fix(native): name the plist selection that works when Info.plist is missing

inspect_plist on a target without a readable default Contents/Info.plist
(for example a bare Mach-O) reported the generic "This analysis is
unavailable for the current target. Choose another analysis or target."
as message and remediation. The specific reason, including "Pass path to
inspect another plist", appeared only in details.reason, although
selecting another plist in the same target is the available workflow.

Pass that reason as the refusal's user message.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/native/NativeMacOSProvider.ts

@@ -819,11 +819,14 @@ const unreadablePlist = (
   reason: string,
 ): AnalysisError => {
   const sentence = reason.endsWith(".") ? reason : `${reason}.`;
+  // Name the default that is missing and the selection that still works.
+  const missingDefault = `The target has no readable Contents/Info.plist at ${path}: ${sentence} Pass path to inspect another plist.`;
   return requested === undefined
     ? new AnalysisCapabilityUnavailableError(
         IDENTITY.id,
         "inspect_plist",
-        `The target has no readable Contents/Info.plist at ${path}: ${sentence} Pass path to inspect another plist.`,
+        missingDefault,
+        { userMessage: missingDefault },
       )
     : new AnalysisInputError("inspect_plist", undefined, [
         {

tests/boundary/cli/nativePlistSelectionFailureCli.test.ts

@@ -113,6 +113,14 @@ describe.skipIf(process.platform !== "darwin")(
         expect(result.exitCode).toBe(1);
         expect(result.json).toMatchObject({
           code: "capability_unavailable",
+          message: expect.stringContaining(
+            "Pass path to inspect another plist",
+          ),
+          remediation: {
+            action: expect.stringContaining(
+              "Pass path to inspect another plist",
+            ),
+          },
           details: {
             operation: "inspect_plist",
             reason: expect.stringContaining(