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/services/oauth.js

@@ -0,0 +1,144 @@
+import { BrowserOAuthClient } from '@atproto/oauth-client-browser'
+import { Agent } from '@atproto/api'
+import { env } from '../config/env.js'
+import { isSyuIsHandle } from '../utils/pds.js'
+
+export class OAuthService {
+  constructor() {
+    this.clientId = env.oauth.clientId || this.getClientId()
+    this.clients = { bsky: null, syu: null }
+    this.agent = null
+    this.sessionInfo = null
+    this.initPromise = null
+  }
+
+  getClientId() {
+    const origin = window.location.origin
+    return origin.includes('localhost') || origin.includes('127.0.0.1')
+      ? undefined // Loopback client
+      : `${origin}/client-metadata.json`
+  }
+
+  async initialize() {
+    if (this.initPromise) return this.initPromise
+    
+    this.initPromise = this._initialize()
+    return this.initPromise
+  }
+
+  async _initialize() {
+    try {
+      // Initialize OAuth clients
+      this.clients.bsky = await BrowserOAuthClient.load({
+        clientId: this.clientId,
+        handleResolver: 'https://bsky.social',
+        plcDirectoryUrl: 'https://plc.directory',
+      })
+
+      this.clients.syu = await BrowserOAuthClient.load({
+        clientId: this.clientId,
+        handleResolver: 'https://syu.is',
+        plcDirectoryUrl: 'https://plc.syu.is',
+      })
+
+      // Try to restore session
+      return await this.restoreSession()
+    } catch (error) {
+      console.error('OAuth initialization failed:', error)
+      this.initPromise = null
+      throw error
+    }
+  }
+
+  async restoreSession() {
+    // Try both clients
+    for (const client of [this.clients.bsky, this.clients.syu]) {
+      const result = await client.init()
+      if (result?.session) {
+        this.agent = new Agent(result.session)
+        return this.processSession(result.session)
+      }
+    }
+    return null
+  }
+
+  async processSession(session) {
+    const did = session.sub || session.did
+    let handle = session.handle || 'unknown'
+
+    this.sessionInfo = { did, handle }
+
+    // Resolve handle if missing
+    if (handle === 'unknown' && this.agent) {
+      try {
+        const profile = await this.agent.getProfile({ actor: did })
+        handle = profile.data.handle
+        this.sessionInfo.handle = handle
+      } catch (error) {
+        console.log('Failed to resolve handle:', error)
+      }
+    }
+
+    return { did, handle }
+  }
+
+  async login(handle) {
+    await this.initialize()
+
+    const client = isSyuIsHandle(handle) ? this.clients.syu : this.clients.bsky
+    const authUrl = await client.authorize(handle, { scope: 'atproto' })
+    
+    window.location.href = authUrl.toString()
+  }
+
+  async checkAuth() {
+    try {
+      await this.initialize()
+      if (this.sessionInfo) {
+        return {
+          user: this.sessionInfo,
+          agent: this.agent
+        }
+      }
+      return null
+    } catch (error) {
+      console.error('Auth check failed:', error)
+      return null
+    }
+  }
+
+  async logout() {
+    try {
+      // Sign out from session
+      if (this.clients.bsky) {
+        const result = await this.clients.bsky.init()
+        if (result?.session?.signOut) {
+          await result.session.signOut()
+        }
+      }
+
+      // Clear state
+      this.agent = null
+      this.sessionInfo = null
+      this.clients = { bsky: null, syu: null }
+      this.initPromise = null
+
+      // Clear storage
+      localStorage.clear()
+      sessionStorage.clear()
+
+      // Reload page
+      window.location.reload()
+    } catch (error) {
+      console.error('Logout failed:', error)
+    }
+  }
+
+  getAgent() {
+    return this.agent
+  }
+
+  getUser() {
+    return this.sessionInfo
+  }
+}