Remove embedded OAuth implementation and flatten directory structure

Simplified the repository to have a single OAuth pattern with separate auth and MCP servers at the top level. Preserved embedded OAuth documentation as an alternative pattern.

embedded-oauth/jest.config.js

@@ -1,19 +0,0 @@
-/** @type {import('ts-jest').JestConfigWithTsJest} */
-export default {
-  preset: 'ts-jest/presets/default-esm',
-  testEnvironment: 'node',
-  extensionsToTreatAsEsm: ['.ts'],
-  moduleNameMapper: {
-    '^(\\.{1,2}/.*)\\.js$': '$1',
-  },
-  transform: {
-    '^.+\\.tsx?$': [
-      'ts-jest',
-      {
-        useESM: true,
-      },
-    ],
-  },
-  testPathIgnorePatterns: ['/node_modules/', '/dist/', '/scratch/'],
-  injectGlobals: true,
-};