feat: Add OIDC authentication with Authentik integration

- Add OIDC login flow with Authentik provider
- Implement session-based auth with Redis store
- Add avatar display from OIDC claims
- Fix input field performance with react-textarea-autosize
- Stabilize callbacks to prevent unnecessary re-renders
- Fix history loading to skip empty session files
- Add 2-row default height for input textarea

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

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

frontend/src/hooks/useClaudeSession.js

@@ -1,7 +1,12 @@
 import { useState, useRef, useCallback, useEffect } from 'react';
 
-const WS_URL = import.meta.env.VITE_WS_URL || 'ws://100.105.142.13:3001';
-const API_URL = import.meta.env.VITE_API_URL || 'http://100.105.142.13:3001';
+// Build WebSocket URL from current location
+function getWsUrl() {
+  if (import.meta.env.VITE_WS_URL) return import.meta.env.VITE_WS_URL;
+  const protocol = window.location.protocol === 'https:' ? 'wss:' : 'ws:';
+  return `${protocol}//${window.location.host}/ws`;
+}
+
 const MAX_FILE_SIZE = 10 * 1024 * 1024; // 10MB
 
 export function useClaudeSession() {
@@ -49,7 +54,7 @@ export function useClaudeSession() {
   const connect = useCallback(() => {
     if (wsRef.current?.readyState === WebSocket.OPEN) return;
 
-    const ws = new WebSocket(WS_URL);
+    const ws = new WebSocket(getWsUrl());
     wsRef.current = ws;
 
     ws.onopen = () => {
@@ -350,7 +355,9 @@ export function useClaudeSession() {
     try {
       const encodedProject = encodeURIComponent(project);
       const hostParam = host ? `?host=${host}` : '';
-      const response = await fetch(`${API_URL}/api/history/${encodedProject}${hostParam}`);
+      const response = await fetch(`/api/history/${encodedProject}${hostParam}`, {
+        credentials: 'include',
+      });
       if (response.ok) {
         const data = await response.json();
         if (data.messages && data.messages.length > 0) {
@@ -397,9 +404,10 @@ export function useClaudeSession() {
     }
 
     try {
-      const response = await fetch(`${API_URL}/api/upload/${sessionId}`, {
+      const response = await fetch(`/api/upload/${sessionId}`, {
         method: 'POST',
-        body: formData
+        body: formData,
+        credentials: 'include',
       });
 
       if (!response.ok) {