feat: RBAC E2E тесты и фикс admin-прав для редактирования постов

Основные изменения:
- Добавлены E2E тесты для проверки ownership (TC-E2E-102/103):
  * test_admin_can_edit_any_post — admin может редактировать любой пост
  * test_user_cannot_edit_other_users_post — user не может редактировать чужой пост
- Исправлены use cases (UpdatePost, DeletePost, PublishPost) — добавлена проверка роли admin
- Обновлены web routes и API routes для передачи роли в use cases
- Добавлены unit тесты для admin-сценариев

Реструктуризация тестов:
- Удалены старые API тесты (tests/api/) — требуют переработки
- Удалены старые integration тесты (tests/integration/)
- Переработаны E2E тесты: удалены старые, добавлены новые с POM
- Добавлена документация тестов: FEATURE_*.md, TEST_MODEL.md, AGENTS.md

Инфраструктура:
- Добавлен MockKeycloakClient для dev-режима
- Добавлены статические файлы: EasyMDE, Highlight.js, стили markdown
- Обновлены шаблоны: base.html, post_form.html, post_detail.html
- Обновлена DI конфигурация и провайдеры

Документация:
- tests/FEATURE_RBAC.md — матрица тестов RBAC
- tests/FEATURE_POST_LIFECYCLE.md — тесты жизненного цикла поста
- tests/FEATURE_DOMAIN_FOUNDATION.md — тесты доменного слоя
- tests/FEATURE_INFRASTRUCTURE.md — тесты инфраструктуры
- tests/TEST_MODEL.md — глобальная матрица покрытия
- app/presentation/web/AGENTS.md — гайд по Web UI
- tests/AGENTS.md — гайд по тестированию

tests/api/conftest.py

@@ -1,145 +0,0 @@
-"""API test fixtures."""
-
-from collections.abc import AsyncGenerator
-from unittest.mock import AsyncMock, MagicMock, patch
-from uuid import uuid4
-
-import pytest
-from httpx import ASGITransport, AsyncClient
-
-from app.application.dtos import PostResponseDTO
-from app.infrastructure.auth.models import TokenInfo
-from app.main import app_factory
-
-
-class MockKeycloakClient:
-    def __init__(self, token_info: TokenInfo) -> None:
-        self._token_info = token_info
-
-    async def introspect_token(self, token: str) -> TokenInfo:
-        return self._token_info
-
-
-@pytest.fixture
-def user_token_info() -> TokenInfo:
-    return TokenInfo(
-        active=True,
-        user_id="test-user-id",
-        username="testuser",
-        email="test@example.com",
-        roles=["user"],
-    )
-
-
-@pytest.fixture
-def admin_token_info() -> TokenInfo:
-    return TokenInfo(
-        active=True,
-        user_id="admin-user-id",
-        username="adminuser",
-        email="admin@example.com",
-        roles=["admin", "user"],
-    )
-
-
-@pytest.fixture
-def mock_keycloak_client(user_token_info: TokenInfo) -> MagicMock:
-    mock_client = AsyncMock()
-    mock_client.introspect_token.return_value = user_token_info
-    return mock_client
-
-
-@pytest.fixture
-async def client(mock_keycloak_client: MagicMock) -> AsyncGenerator[AsyncClient]:
-    with patch(
-        "app.presentation.api.deps.KeycloakAuthClient",
-        return_value=mock_keycloak_client,
-    ):
-        app = app_factory()
-        transport = ASGITransport(app=app)
-        async with AsyncClient(transport=transport, base_url="http://test") as ac:
-            yield ac
-
-
-@pytest.fixture
-async def auth_client(user_token_info: TokenInfo) -> AsyncGenerator[AsyncClient]:
-    mock_client = MockKeycloakClient(user_token_info)
-
-    with patch(
-        "app.presentation.api.deps.get_keycloak_client",
-        return_value=mock_client,
-    ):
-        app = app_factory()
-        transport = ASGITransport(app=app)
-        async with AsyncClient(
-            transport=transport,
-            base_url="http://test",
-            headers={"Authorization": "Bearer user_token"},
-        ) as ac:
-            yield ac
-
-
-@pytest.fixture
-async def admin_client(admin_token_info: TokenInfo) -> AsyncGenerator[AsyncClient]:
-    mock_client = MockKeycloakClient(admin_token_info)
-
-    with patch(
-        "app.presentation.api.deps.get_keycloak_client",
-        return_value=mock_client,
-    ):
-        app = app_factory()
-        transport = ASGITransport(app=app)
-        async with AsyncClient(
-            transport=transport,
-            base_url="http://test",
-            headers={"Authorization": "Bearer admin_token"},
-        ) as ac:
-            yield ac
-
-
-@pytest.fixture
-def auth_headers() -> dict[str, str]:
-    return {"Authorization": "Bearer test_token"}
-
-
-@pytest.fixture
-def unauthorized_keycloak_client() -> MagicMock:
-    mock_client = AsyncMock()
-    mock_client.introspect_token.return_value = TokenInfo(
-        active=False,
-        user_id="",
-        username="",
-        email="",
-        roles=[],
-    )
-    return mock_client
-
-
-@pytest.fixture
-def sample_post_dto() -> PostResponseDTO:
-    return PostResponseDTO(
-        id=uuid4(),
-        title="Test Post",
-        content="This is test content for the blog post",
-        slug="test-post",
-        author_id="test-user-id",
-        published=True,
-        tags=["python", "testing"],
-        created_at=__import__("datetime").datetime.now(),
-        updated_at=__import__("datetime").datetime.now(),
-    )
-
-
-@pytest.fixture
-def sample_unpublished_post_dto() -> PostResponseDTO:
-    return PostResponseDTO(
-        id=uuid4(),
-        title="Draft Post",
-        content="This is a draft post",
-        slug="draft-post",
-        author_id="test-user-id",
-        published=False,
-        tags=["draft"],
-        created_at=__import__("datetime").datetime.now(),
-        updated_at=__import__("datetime").datetime.now(),
-    )