MCP server tool names exceed 64-character API limit

## Summary

The MCP server names defined in `.mcp.json` cause tool names to exceed the 64-character limit enforced by the Claude API, resulting in `invalid_request_error` when using the plugin.

## Error

```
{"type":"error","error":{"type":"invalid_request_error","message":"messages.X.content.0.tool_result.content.0.tool_reference.tool_name: String should have at most 64 characters"}}
```

## Root Cause

Claude Code prefixes MCP tool names with `mcp__plugin_cloudflare_`, then appends the server name and tool name. The current server names in `.mcp.json` create excessively long prefixes:

| Server Name | Full Prefix | Length |
|-------------|-------------|--------|
| `cloudflare-docs` | `mcp__plugin_cloudflare_cloudflare-docs__` | 41 |
| `cloudflare-workers-observability` | `mcp__plugin_cloudflare_cloudflare-workers-observability__` | 56 |
| `cloudflare-workers-builds` | `mcp__plugin_cloudflare_cloudflare-workers-builds__` | 49 |

When combined with tool names like `query_worker_observability` (26 chars), the total exceeds 64 characters.

## Suggested Fix

Remove the redundant `cloudflare-` prefix from server names since it's already included in the plugin prefix:

```json
{
"mcpServers": {
"docs": {
"command": "npx",
"args": ["mcp-remote", "https://docs.mcp.cloudflare.com/mcp"]
},
"observability": {
"command": "npx",
"args": ["mcp-remote", "https://observability.mcp.cloudflare.com/mcp"]
},
"builds": {
"command": "npx",
"args": ["mcp-remote", "https://builds.mcp.cloudflare.com/mcp"]
}
}
}
```

This would create prefixes of 29-38 characters, leaving ample room for tool names.

## Environment

- Claude Code CLI
- Cloudflare skills plugin (commit 3f72589, 2026-01-28)