Add scheduler handoff runner for selected prompts

scripts/agent/run-selected-prompt.mjs

@@ -0,0 +1,74 @@
+#!/usr/bin/env node
+import fs from 'node:fs/promises';
+import path from 'node:path';
+import { spawn } from 'node:child_process';
+
+const REQUIRED_ENV = ['SCHEDULER_PROMPT_PATH', 'SCHEDULER_AGENT', 'SCHEDULER_CADENCE'];
+
+function fail(message, code = 1) {
+  console.error(`[scheduler] ${message}`);
+  process.exit(code);
+}
+
+function resolveRunner(promptMarkdown) {
+  const customRunner = process.env.SCHEDULER_AGENT_RUNNER_COMMAND?.trim();
+  if (customRunner) {
+    return { command: 'bash', args: ['-lc', customRunner] };
+  }
+
+  const platform = (process.env.AGENT_PLATFORM || 'codex').trim().toLowerCase();
+  if (platform === 'codex') {
+    return { command: 'codex', args: ['exec', promptMarkdown] };
+  }
+
+  if (platform === 'claude') {
+    return { command: 'claude', args: ['-p', promptMarkdown] };
+  }
+
+  fail(`Unsupported AGENT_PLATFORM="${platform}". Set SCHEDULER_AGENT_RUNNER_COMMAND to override.`);
+}
+
+async function main() {
+  for (const key of REQUIRED_ENV) {
+    if (!process.env[key] || !String(process.env[key]).trim()) {
+      fail(`Missing required environment variable ${key}.`);
+    }
+  }
+
+  const promptPath = path.resolve(process.cwd(), process.env.SCHEDULER_PROMPT_PATH);
+  let promptMarkdown;
+
+  try {
+    promptMarkdown = await fs.readFile(promptPath, 'utf8');
+  } catch {
+    fail(`Unable to read scheduler prompt at ${promptPath}.`);
+  }
+
+  if (!promptMarkdown.trim()) {
+    fail(`Scheduler prompt at ${promptPath} is empty.`);
+  }
+
+  const runner = resolveRunner(promptMarkdown);
+  const child = spawn(runner.command, runner.args, {
+    cwd: process.cwd(),
+    env: {
+      ...process.env,
+      SCHEDULER_PROMPT_PATH: promptPath,
+      SCHEDULER_PROMPT_MARKDOWN: promptMarkdown,
+    },
+    stdio: 'inherit',
+  });
+
+  child.on('error', (error) => {
+    if (error.code === 'ENOENT') {
+      fail(`Runner command not found: ${runner.command}`, 127);
+    }
+    fail(`Runner execution failed: ${error.message}`);
+  });
+
+  child.on('close', (code) => {
+    process.exit(code ?? 1);
+  });
+}
+
+main();