Add admin panel, WebSocket support, and API versioning

Introduce an admin portal (React + Nginx), WebSocket routing, and
API versioning middleware with `/api/v1/` prefix deprecation.
Add master API key authentication, new Prometheus metrics for AI
token consumption and active WebSockets, and extend S3 config
with a public endpoint URL. Update test paths and fixtures to
align with the new routing structure.

tests/test_ai_vision_internals.py

@@ -2,7 +2,7 @@ import pytest
 import os
 import base64
 from pathlib import Path
-from unittest.mock import patch, MagicMock
+from unittest.mock import patch, MagicMock, AsyncMock
 from app.services.ai_vision import (
     _read_image, _extract_json, _usage_tokens_gemini, 
     _generate_gemini, _generate_openrouter, _generate,
@@ -10,11 +10,12 @@ from app.services.ai_vision import (
 )
 from app.config import settings
 
-def test_read_image_variants(tmp_path):
+@pytest.mark.asyncio
+async def test_read_image_variants(tmp_path):
     img_file = tmp_path / "test.png"
     img_file.write_bytes(b"fake_png_data")
     
-    data, mime = _read_image(str(img_file))
+    data, mime = await _read_image(str(img_file))
     assert data == b"fake_png_data"
     assert mime == "image/png"
 
@@ -67,7 +68,7 @@ async def test_generate_dispatcher_openrouter(mock_settings, mock_gen_or):
 
 @pytest.mark.asyncio
 @patch("app.services.ai_vision._generate")
-@patch("app.services.ai_vision._read_image")
+@patch("app.services.ai_vision._read_image", new_callable=AsyncMock)
 @patch("app.services.ai_vision.settings")
 async def test_extract_text_with_ai(mock_settings, mock_read_image, mock_generate):
     mock_settings.AI_ENABLED = True
@@ -83,7 +84,7 @@ async def test_extract_text_with_ai(mock_settings, mock_read_image, mock_generat
 
 @pytest.mark.asyncio
 @patch("app.services.ai_vision._generate")
-@patch("app.services.ai_vision._read_image")
+@patch("app.services.ai_vision._read_image", new_callable=AsyncMock)
 @patch("app.services.ai_vision.settings")
 async def test_analyze_image_failure(mock_settings, mock_read_image, mock_generate):
     mock_settings.AI_ENABLED = True