[Dev UI] Unable to use prompts in runner

[MichaelDoyle]

In the prompt runner, even if a prompt has a schema in its definition, no input schema is detected so the input box is not rendered. The schema is not present in the prompt metadata.

"/executable-prompt/code-review": {
  "metadata": {
    "type": "executable-prompt",
    "prompt": {
      "template": "You are a senior software engineer and code reviewer with expertise in {{language}}.\n\nAnalyze the following {{language}} code:\n\n```{{language}}\n{{code}}\n```\n\n{{#if analysisType}}\nFocus on: {{analysisType}}\n{{else}}\nProvide a comprehensive analysis including:\n- Code quality and readability\n- Potential bugs or issues\n- Performance considerations\n- Best practices adherence\n{{/if}}\n\nIMPORTANT: You MUST respond with ONLY a valid JSON object matching the output schema. Do not include any explanatory text before or after the JSON.\n\nReturn your analysis in the specified JSON format.",
      "name": "code-review",
      "model": "openai/gpt-4o-mini"
    }
  },
  "outputSchema": null,
  "inputSchema": null,
  "name": "code-review",
  "description": null,
  "key": "/executable-prompt/code-review"
}