refactor(adb): encode package verdict certainty in the result type

src/adb/AdbProvider.ts

@@ -2693,7 +2693,7 @@ export class AdbProvider {
             new AnalysisUnsupportedTargetError(
               operation,
               input.serial,
-              verdict.reason ?? "the device refused the installation",
+              verdict.reason,
             ),
           );
         return ok(
@@ -2767,7 +2767,7 @@ export class AdbProvider {
         new AnalysisUnsupportedTargetError(
           operation,
           input.serial,
-          verdict.reason ?? "the device refused the removal",
+          verdict.reason,
         ),
       );
     return ok(

src/adb/AdbShellOutput.ts

@@ -418,10 +418,9 @@ export const packageChangeFailureReason = (output: string): string | null =>
  */
 export const parsePackageChangeOutput = (
   stdout: string,
-): {
-  readonly status: "success" | "failure" | "unknown";
-  readonly reason: string | null;
-} => {
+):
+  | { readonly status: "success" | "unknown"; readonly reason: null }
+  | { readonly status: "failure"; readonly reason: string } => {
   const text = stdout.trim();
   const failure = packageChangeFailureReason(text);
   if (failure !== null) return { status: "failure", reason: failure };