Add oauth_new: Complete OAuth authentication and comment system

- Created new oauth_new directory with clean OAuth implementation
- Added 4-tab interface: Lang, Comment, Collection, User Comments
- Implemented OAuth authentication with @atproto/oauth-client-browser
- Added comment posting functionality with putRecord
- Added proper PDS detection and error handling
- Skipped placeholder users to prevent errors
- Built comprehensive documentation (README.md, DEVELOPMENT.md)

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

oauth_new/src/hooks/usePageContext.js

@@ -0,0 +1,33 @@
+import { useState, useEffect } from 'react'
+
+export function usePageContext() {
+  const [pageContext, setPageContext] = useState({
+    isTopPage: true,
+    rkey: null,
+    url: null
+  })
+
+  useEffect(() => {
+    const pathname = window.location.pathname
+    const url = window.location.href
+
+    // Extract rkey from URL pattern: /posts/xxx or /posts/xxx.html
+    const match = pathname.match(/\/posts\/([^/]+)\/?$/)
+    if (match) {
+      const rkey = match[1].replace(/\.html$/, '')
+      setPageContext({
+        isTopPage: false,
+        rkey,
+        url
+      })
+    } else {
+      setPageContext({
+        isTopPage: true,
+        rkey: null,
+        url
+      })
+    }
+  }, [])
+
+  return pageContext
+}