Add subscription migration list command

[tyler-eon]

What this changes

Adds the subscription migration command:

shopify app subscription-migrations list

The command:

• fetches every page from the new migratableAppSubscriptions Partners CLI GraphQL query;
• optionally filters by UNSCHEDULED, SCHEDULED, or MIGRATED;
• streams a comprehensive CSV to stdout by default;
• streams one versioned JSON document to stdout with --json;
• supports saving either format through normal shell redirection;

The read model can preserve historical NONE notification values returned by the API without re-enabling NONE as a schedule-input option.

Examples

shopify app subscription-migrations list
shopify app subscription-migrations list --status UNSCHEDULED
shopify app subscription-migrations list --json
shopify app subscription-migrations list > subscriptions.csv
shopify app subscription-migrations list --json > subscriptions.json

Verification

• 22 focused test files: 251 passed, 1 platform-specific skip
• App and CLI Kit type-checks
• App, CLI, and CLI Kit builds
• ESLint
• Knip
• Oclif manifest generation
• Command snapshot validation
• Direct hidden-command help and normal-discovery checks
• CSV escaping, JSON schema, stdout purity, nullable API response, and cursor pagination coverage

[github-actions]

Differences in type declarations

We detected differences in the type declarations generated by Typescript for this branch compared to the baseline ('main' branch). Please, review them to ensure they are backward-compatible. Here are some important things to keep in mind:

• Some seemingly private modules might be re-exported through public modules.
• If the branch is behind main you might see odd diffs, rebase main into this branch.

New type declarations

We found no new type declarations in this PR

Existing type declarations

packages/cli-kit/dist/public/node/fs.d.ts

@@ -86,6 +86,7 @@ export declare function appendFile(path: string, content: string): Promise<void>
 export declare function appendFileSync(path: string, data: string): void;
 export interface WriteOptions {
     encoding: BufferEncoding;
+    flag?: 'w' | 'wx';
 }
 /**
  * Writes content to file at path.

[dmerand]

This LGTM from a code standpoint. My comments about output format are non-blocking, though my opinion is that we don't need so much code to handle output formatting when that's already handled well-enough by the OS.