Add PostCSS configuration and skills lock file

- Created a new PostCSS configuration file to integrate Tailwind CSS.
- Added a skills lock file containing various Expo skills with their respective source and computed hashes.

.agents/skills/expo-cicd-workflows/SKILL.md

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+---
+name: expo-cicd-workflows
+description: Helps understand and write EAS workflow YAML files for Expo projects. Use this skill when the user asks about CI/CD or workflows in an Expo or EAS context, mentions .eas/workflows/, or wants help with EAS build pipelines or deployment automation.
+allowed-tools: "Read,Write,Bash(node:*)"
+version: 1.0.0
+license: MIT License
+---
+
+# EAS Workflows Skill
+
+Help developers write and edit EAS CI/CD workflow YAML files.
+
+## Reference Documentation
+
+Fetch these resources before generating or validating workflow files. Use the fetch script (implemented using Node.js) in this skill's `scripts/` directory; it caches responses using ETags for efficiency:
+
+```bash
+# Fetch resources
+node {baseDir}/scripts/fetch.js <url>
+```
+
+1. **JSON Schema** — https://api.expo.dev/v2/workflows/schema
+   - It is NECESSARY to fetch this schema
+   - Source of truth for validation
+   - All job types and their required/optional parameters
+   - Trigger types and configurations
+   - Runner types, VM images, and all enums
+
+2. **Syntax Documentation** — https://raw.githubusercontent.com/expo/expo/refs/heads/main/docs/pages/eas/workflows/syntax.mdx
+   - Overview of workflow YAML syntax
+   - Examples and English explanations
+   - Expression syntax and contexts
+
+3. **Pre-packaged Jobs** — https://raw.githubusercontent.com/expo/expo/refs/heads/main/docs/pages/eas/workflows/pre-packaged-jobs.mdx
+   - Documentation for supported pre-packaged job types
+   - Job-specific parameters and outputs
+
+Do not rely on memorized values; these resources evolve as new features are added.
+
+## Workflow File Location
+
+Workflows live in `.eas/workflows/*.yml` (or `.yaml`).
+
+## Top-Level Structure
+
+A workflow file has these top-level keys:
+
+- `name` — Display name for the workflow
+- `on` — Triggers that start the workflow (at least one required)
+- `jobs` — Job definitions (required)
+- `defaults` — Shared defaults for all jobs
+- `concurrency` — Control parallel workflow runs
+
+Consult the schema for the full specification of each section.
+
+## Expressions
+
+Use `${{ }}` syntax for dynamic values. The schema defines available contexts:
+
+- `github.*` — GitHub repository and event information
+- `inputs.*` — Values from `workflow_dispatch` inputs
+- `needs.*` — Outputs and status from dependent jobs
+- `jobs.*` — Job outputs (alternative syntax)
+- `steps.*` — Step outputs within custom jobs
+- `workflow.*` — Workflow metadata
+
+## Generating Workflows
+
+When generating or editing workflows:
+
+1. Fetch the schema to get current job types, parameters, and allowed values
+2. Validate that required fields are present for each job type
+3. Verify job references in `needs` and `after` exist in the workflow
+4. Check that expressions reference valid contexts and outputs
+5. Ensure `if` conditions respect the schema's length constraints
+
+## Validation
+
+After generating or editing a workflow file, validate it against the schema:
+
+```sh
+# Install dependencies if missing
+[ -d "{baseDir}/scripts/node_modules" ] || npm install --prefix {baseDir}/scripts
+
+node {baseDir}/scripts/validate.js <workflow.yml> [workflow2.yml ...]
+```
+
+The validator fetches the latest schema and checks the YAML structure. Fix any reported errors before considering the workflow complete.
+
+## Answering Questions
+
+When users ask about available options (job types, triggers, runner types, etc.), fetch the schema and derive the answer from it rather than relying on potentially outdated information.

.agents/skills/expo-cicd-workflows/scripts/fetch.js

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+#!/usr/bin/env node
+
+import { createHash } from 'node:crypto';
+import { readFile, writeFile, mkdir } from 'node:fs/promises';
+import { resolve } from 'node:path';
+import process from 'node:process';
+
+const CACHE_DIRECTORY = resolve(import.meta.dirname, '.cache');
+const DEFAULT_TTL_SECONDS = 15 * 60; // 15 minutes
+
+export async function fetchCached(url) {
+  await mkdir(CACHE_DIRECTORY, { recursive: true });
+
+  const cacheFile = resolve(CACHE_DIRECTORY, hashUrl(url) + '.json');
+  const cached = await loadCacheEntry(cacheFile);
+  if (cached && cached.expires > Math.floor(Date.now() / 1000)) {
+    return cached.data;
+  }
+
+  // Make request, with conditional If-None-Match if we have an ETag.
+  // Cache-Control: max-age=0 overrides Node's default 'no-cache' to allow 304 responses.
+  const response = await fetch(url, {
+    headers: {
+      'Cache-Control': 'max-age=0',
+      ...(cached?.etag && { 'If-None-Match': cached.etag }),
+    },
+  });
+
+  if (response.status === 304 && cached) {
+    // Refresh expiration and return cached data
+    const entry = { ...cached, expires: getExpires(response.headers) };
+    await saveCacheEntry(cacheFile, entry);
+    return cached.data;
+  }
+
+  if (!response.ok) {
+    throw new Error(`HTTP ${response.status}: ${response.statusText}`);
+  }
+
+  const etag = response.headers.get('etag');
+  const data = await response.text();
+  const expires = getExpires(response.headers);
+
+  await saveCacheEntry(cacheFile, { url, etag, expires, data });
+
+  return data;
+}
+
+function hashUrl(url) {
+  return createHash('sha256').update(url).digest('hex').slice(0, 16);
+}
+
+async function loadCacheEntry(cacheFile) {
+  try {
+    return JSON.parse(await readFile(cacheFile, 'utf-8'));
+  } catch {
+    return null;
+  }
+}
+
+async function saveCacheEntry(cacheFile, entry) {
+  await writeFile(cacheFile, JSON.stringify(entry, null, 2));
+}
+
+function getExpires(headers) {
+  const now = Math.floor(Date.now() / 1000);
+
+  // Prefer Cache-Control: max-age
+  const maxAgeSeconds = parseMaxAge(headers.get('cache-control'));
+  if (maxAgeSeconds != null) {
+    return now + maxAgeSeconds;
+  }
+
+  // Fall back to Expires header
+  const expires = headers.get('expires');
+  if (expires) {
+    const expiresTime = Date.parse(expires);
+    if (!Number.isNaN(expiresTime)) {
+      return Math.floor(expiresTime / 1000);
+    }
+  }
+
+  // Default TTL
+  return now + DEFAULT_TTL_SECONDS;
+}
+
+function parseMaxAge(cacheControl) {
+  if (!cacheControl) {
+    return null;
+  }
+  const match = cacheControl.match(/max-age=(\d+)/i);
+  return match ? parseInt(match[1], 10) : null;
+}
+
+if (import.meta.main) {
+  const url = process.argv[2];
+
+  if (!url || url === '--help' || url === '-h') {
+    console.log(`Usage: fetch <url>
+
+Fetches a URL with HTTP caching (ETags + Cache-Control/Expires).
+Default TTL: ${DEFAULT_TTL_SECONDS / 60} minutes.
+Cache is stored in: ${CACHE_DIRECTORY}/`);
+    process.exit(url ? 0 : 1);
+  }
+
+  const data = await fetchCached(url);
+  console.log(data);
+}

.agents/skills/expo-cicd-workflows/scripts/package.json

@@ -0,0 +1,11 @@
+{
+  "name": "@expo/cicd-workflows-skill",
+  "version": "0.0.0",
+  "private": true,
+  "type": "module",
+  "dependencies": {
+    "ajv": "^8.17.1",
+    "ajv-formats": "^3.0.1",
+    "js-yaml": "^4.1.0"
+  }
+}

.agents/skills/expo-cicd-workflows/scripts/validate.js

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+#!/usr/bin/env node
+
+import { readFile } from 'node:fs/promises';
+import { resolve } from 'node:path';
+import process from 'node:process';
+
+import Ajv2020 from 'ajv/dist/2020.js';
+import addFormats from 'ajv-formats';
+import yaml from 'js-yaml';
+
+import { fetchCached } from './fetch.js';
+
+const SCHEMA_URL = 'https://api.expo.dev/v2/workflows/schema';
+
+async function fetchSchema() {
+  const data = await fetchCached(SCHEMA_URL);
+  const body = JSON.parse(data);
+  return body.data;
+}
+
+function createValidator(schema) {
+  const ajv = new Ajv2020({ allErrors: true, strict: true });
+  addFormats(ajv);
+  return ajv.compile(schema);
+}
+
+async function validateFile(validator, filePath) {
+  const content = await readFile(filePath, 'utf-8');
+
+  let doc;
+  try {
+    doc = yaml.load(content);
+  } catch (e) {
+    return { valid: false, error: `YAML parse error: ${e.message}` };
+  }
+
+  const valid = validator(doc);
+  if (!valid) {
+    return { valid: false, error: formatErrors(validator.errors) };
+  }
+
+  return { valid: true };
+}
+
+function formatErrors(errors) {
+  return errors
+    .map((error) => {
+      const path = error.instancePath || '(root)';
+      const allowed = error.params?.allowedValues?.join(', ');
+      return `  ${path}: ${error.message}${allowed ? ` (allowed: ${allowed})` : ''}`;
+    })
+    .join('\n');
+}
+
+if (import.meta.main) {
+  const args = process.argv.slice(2);
+  const files = args.filter((a) => !a.startsWith('-'));
+
+  if (files.length === 0 || args.includes('--help') || args.includes('-h')) {
+    console.log(`Usage: validate <workflow.yml> [workflow2.yml ...]
+
+Validates EAS workflow YAML files against the official schema.`);
+    process.exit(files.length === 0 ? 1 : 0);
+  }
+
+  const schema = await fetchSchema();
+  const validator = createValidator(schema);
+
+  let hasErrors = false;
+
+  for (const file of files) {
+    const filePath = resolve(process.cwd(), file);
+    const result = await validateFile(validator, filePath);
+
+    if (result.valid) {
+      console.log(`✓ ${file}`);
+    } else {
+      console.error(`✗ ${file}\n${result.error}`);
+      hasErrors = true;
+    }
+  }
+
+  process.exit(hasErrors ? 1 : 0);
+}