execute mishandles successful JSON responses without Cloudflare REST envelope

## Current behavior

Code Mode `cloudflare.request()` assumes successful API responses are either literal `application/json` using the traditional Cloudflare `{ success, result, errors, ... }` envelope, or non-JSON text. Current Cloudflare APIs include successful JSON responses that satisfy neither assumption.

### Reproducer 1: direct `application/json` object

A successful Analytics Engine SQL response such as:

```json
{"data":[[1]],"meta":[{"name":"count","type":"UInt64"}],"rows":1}
```

is parsed as JSON, but because it has no `success` property the helper throws:

```text
Error: Cloudflare API error: 200
```

I reproduced this through the real MCP `execute` path and Worker Loader on Node 22.23.2.

### Reproducer 2: vendor JSON (`application/scim+json`)

A successful SCIM Groups response such as:

```json
{"Resources":[{"id":"g1","displayName":"Admins"}],"totalResults":1}
```

is treated as raw text because its media type does not contain the literal string `application/json`. Normal structured access such as `response.result.Resources[0]` therefore fails.

## Scope evidence

A scan of the current Cloudflare OpenAPI schema found at least 210 obvious successful `application/json` response schemas whose top-level shape is an array, primitive, or object without a `success` field. Examples include Analytics Engine SQL, Browser Rendering DevTools, Brand Protection, and Cloudforce One endpoints.

The schema also contains 30 `application/scim+json` response entries across SCIM Groups, Users, Schemas, ResourceTypes, and ServiceProviderConfig, including successful 2xx responses.

## Root cause

`src/tools/execute.ts` recognizes JSON only when `responseContentType.includes("application/json")`, then treats any parsed payload with falsy/missing `data.success` as a Cloudflare API failure. Recognizing `+json` alone would therefore be incomplete: successful JSON APIs that do not use the legacy REST envelope need a deliberate normalization path too.

## Expected behavior

Successful JSON-compatible responses should remain usable as structured data through `cloudflare.request()`. Traditional Cloudflare envelope responses should keep their current normalized behavior, while successful direct JSON objects/arrays/primitives and vendor-JSON payloads should not become false errors or raw strings.

## Duplicate / ownership check

I searched open/closed issues and PRs for direct JSON success envelopes, Analytics Engine `Cloudflare API error: 200`, SCIM, `application/scim+json`, vendor JSON, and execute response content-type handling and did not find a matching report or active fix.

If this is useful, I can take the implementation once assigned or approved.

## AI / agent disclosure

This report was prepared and reproduced with assistance from an autonomous AI coding agent operated by Keeltrace.