Add SaaS AI engine (#5907)

engine/pyproject.toml

@@ -0,0 +1,69 @@
+[project]
+name = "engine"
+version = "0.1.0"
+description = "AI Document Engine"
+requires-python = ">=3.13"
+dependencies = [
+    "flask>=3.0.0",
+    "flask-cors>=4.0.0",
+    "gunicorn>=25.0.3",
+    "openai>=2.20.0",
+    "langchain-core>=1.2.11",
+    "langchain-openai>=1.1.9",
+    "langchain-anthropic>=1.1.9",
+    "platformdirs>=4.5.1",
+    "pypdf>=6.7.0",
+    "pydantic>=2.0.0",
+    "posthog>=7.8.6",
+    "python-dotenv>=1.2.1",
+    "beautifulsoup4>=4.12.0",
+]
+
+[dependency-groups]
+dev = [
+    "pytest>=8.0.0",
+    "pytest-cov>=4.1.0",
+    "ruff>=0.14.10",
+    "pyright>=1.1.408",
+    "datamodel-code-generator[ruff]>=0.27.0",
+]
+
+[build-system]
+requires = ["hatchling"]
+build-backend = "hatchling.build"
+
+[tool.hatch.build.targets.wheel]
+packages = ["src"]
+exclude = [
+    "tests",
+]
+
+[tool.ruff]
+line-length = 120
+target-version = "py313"
+
+[tool.ruff.lint]
+select = [
+    "E",
+    "F",
+    "I",
+    "N",
+    "W",
+    "RUF100",
+    "UP",
+]
+ignore = [
+    "E501", # Temporarily disable line length limit until codebase conformat
+]
+
+[tool.pyright]
+pythonVersion = "3.13"
+
+reportImportCycles = "warning"
+reportUnnecessaryCast = "warning"
+reportUnusedImport = "warning"
+#reportUnknownParameterType = "warning"
+
+[tool.pytest.ini_options]
+testpaths = ["tests"]
+pythonpath = ["src"]