Add typed JSON output to theme check

[gonzaloriestra]

WHY are these changes introduced?

theme check --output json has an existing result shape but no discoverable schema or standard --json flag.

Related to shop/issues-develop#23691.

WHAT is this pull request doing?

Add typed check results and --json, preserving compact JSON, offense ordering, text output, auto-correction and failure exits. Keep the text adapter used by theme push.

Normal output for a clean theme:

Theme Check Summary.
1 files inspected with no offenses found.

Matching JSON:

[]

Multiple environments emit one ordered {environments: [{environment, result}]} document for both JSON flags. Failed environments remain on stderr and are omitted. --json is incompatible with --init, --version, --print, and --list; those modes keep their existing behavior without --json.

Refreshes generated help and the manifest.

How to manually test your changes?

shopify theme check --path ./theme
shopify theme check --path ./theme --json
shopify theme check --path ./theme --output json
shopify theme check --json-schema
shopify theme check --environment development --environment staging --json

Checklist

• I've considered possible cross-platform impacts (Mac, Linux, Windows)
• I've considered possible documentation changes
• I've considered analytics changes to measure impact
• A single changeset for all theme migrations is added in the last PR, #8682.

[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/base-command.d.ts

@@ -35,6 +35,7 @@ declare abstract class BaseCommand extends Command {
         argv: string[];
     }>;
     protected environmentsFilename(): string | undefined;
+    protected validateNonTTYFlags(flags: FlagOutput): void;
     protected failMissingNonTTYFlags(flags: FlagOutput, requiredFlags: string[]): void;
     private failMissingNonTTYFlagRequirements;
     private applicableNonTTYFlagRequirements;