Add typed JSON output to theme publish

[gonzaloriestra]

WHY are these changes introduced?

theme publish has no JSON result contract, so automation must parse terminal output.

Part of shop/issues-develop#23692.

WHAT is this pull request doing?

Return status: "success" alongside the published theme, using the shared mutation success schema. Multiple environments carry the status inside each successful result, with no overall success claim.

Return the published API theme as typed data and move final output into a presenter. Reuse the environment collector from the preceding PR, retaining prompts and the original terminal wording. Add --json, expose the domain-owned schema, and refresh the manifest, README, and generated docs.

Normal output includes:

The theme 'Original' (#1) is now live at https://example.myshopify.com.

Matching JSON:

{
  "status": "success",
  "theme": {
    "id": 1,
    "name": "Original",
    "role": "live",
    "processing": false,
    "createdAtRuntime": false,
    "shop": "example.myshopify.com"
  }
}

The optional src field is retained when present. Multiple environments return {"environments":[{"environment":"staging","result":...}]} in configured order. Failed or invalid environments are omitted and reported on stderr; total failure returns {"environments":[]}. Existing exit behavior and single-environment presentation are preserved.

How to manually test your changes?

pnpm shopify theme publish --help
pnpm shopify theme publish --json-schema
pnpm shopify theme publish --store "$STORE" --theme "$THEME_ID" --force
pnpm shopify theme publish --store "$STORE" --theme "$THEME_ID" --force --json
pnpm shopify theme publish --environment staging --environment production --theme "$THEME_ID" --force --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;