chore: replace all node/npm/tsx references with bun across codebase

- Source: setup/service.ts, runners.ts, agent-runner.ts error messages
- Scripts: restart-stack.sh, run-migrations.ts → bun
- Bootstrap: setup.sh check_node→check_bun, npm install→bun install
- Docs: CLAUDE.md, README.md, all SKILL.md files
- Tests: service.test.ts, restart-stack.test.ts expectations updated

scripts/restart-ejclaw-stack.sh

@@ -5,4 +5,4 @@ SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 PROJECT_ROOT="$(cd "${SCRIPT_DIR}/.." && pwd)"
 
 cd "${PROJECT_ROOT}"
-npx tsx setup/restart-stack.ts "$@"
+bun setup/restart-stack.ts "$@"

scripts/run-migrations.ts

@@ -1,4 +1,4 @@
-#!/usr/bin/env tsx
+#!/usr/bin/env bun
 import { execFileSync, execSync } from 'child_process';
 import fs from 'fs';
 import path from 'path';
@@ -13,20 +13,16 @@ function compareSemver(a: string, b: string): number {
   return 0;
 }
 
-// Resolve tsx binary once to avoid npx race conditions across migrations
-function resolveTsx(): string {
-  // Check local node_modules first
-  const local = path.resolve('node_modules/.bin/tsx');
-  if (fs.existsSync(local)) return local;
-  // Fall back to whichever tsx is in PATH
+// Resolve bun binary once
+function resolveBun(): string {
   try {
-    return execSync('which tsx', { encoding: 'utf-8' }).trim();
+    return execSync('which bun', { encoding: 'utf-8' }).trim();
   } catch {
-    return 'npx'; // last resort
+    return 'bun'; // last resort
   }
 }
 
-const tsxBin = resolveTsx();
+const bunBin = resolveBun();
 
 const fromVersion = process.argv[2];
 const toVersion = process.argv[3];
@@ -34,7 +30,7 @@ const newCorePath = process.argv[4];
 
 if (!fromVersion || !toVersion || !newCorePath) {
   console.error(
-    'Usage: tsx scripts/run-migrations.ts <from-version> <to-version> <new-core-path>',
+    'Usage: bun scripts/run-migrations.ts <from-version> <to-version> <new-core-path>',
   );
   process.exit(1);
 }
@@ -80,10 +76,7 @@ for (const version of migrationVersions) {
   }
 
   try {
-    const tsxArgs = tsxBin.endsWith('npx')
-      ? ['tsx', migrationIndex, projectRoot]
-      : [migrationIndex, projectRoot];
-    execFileSync(tsxBin, tsxArgs, {
+    execFileSync(bunBin, [migrationIndex, projectRoot], {
       stdio: 'pipe',
       cwd: projectRoot,
       timeout: 120_000,