Add typed JSON output to theme profile

[gonzaloriestra]

WHY are these changes introduced?

theme profile --json returns Speedscope data without a discoverable result contract.

Related to shop/issues-develop#23691.

WHAT is this pull request doing?

Return validated Speedscope data and move JSON/browser presentation into a presenter. Preserve the server's original JSON bytes, including whitespace, field order and extension fields. JSON progress uses the shared typed event channel on stderr; text output retains the existing task display, generated files and browser behavior.

Normal output shows the profiling task and opens the profile in Speedscope:

Generating Liquid profile for example.myshopify.com /

Matching JSON example:

{
  "$schema": "https://www.speedscope.app/file-format-schema.json",
  "shared": {"frames": [{"name": "layout/theme.liquid"}]},
  "profiles": [{
    "type": "evented",
    "name": "Liquid",
    "unit": "microseconds",
    "startValue": 0,
    "endValue": 10,
    "events": [{"type": "O", "at": 0, "frame": 0}, {"type": "C", "at": 10, "frame": 0}]
  }]
}

Uses the bundled Speedscope format for schema definitions and refreshes generated help and the manifest.

How to manually test your changes?

shopify theme profile --store example.myshopify.com --url /
shopify theme profile --store example.myshopify.com --url / --json
shopify theme profile --json-schema

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;