Redesign Python AI engine (#5991)

# Description of Changes
Redesign the Python AI engine to be properly agentic and make use of
`pydantic-ai` instead of `langchain` for correctness and ergonomics.
This should be a good foundation for us to build our AI engine on going
forwards.

engine/pyproject.toml

@@ -4,28 +4,19 @@ 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",
+    "fastapi>=0.116.0",
     "pydantic>=2.0.0",
-    "posthog>=7.8.6",
+    "pydantic-ai>=1.67.0",
+    "pydantic-settings>=2.0.0",
     "python-dotenv>=1.2.1",
-    "beautifulsoup4>=4.12.0",
+    "uvicorn>=0.35.0",
 ]
 
 [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",
+    "ruff>=0.14.10",
 ]
 
 [build-system]
@@ -61,8 +52,9 @@ pythonVersion = "3.13"
 
 reportImportCycles = "warning"
 reportUnnecessaryCast = "warning"
+reportUnnecessaryTypeIgnoreComment = "warning"
 reportUnusedImport = "warning"
-#reportUnknownParameterType = "warning"
+reportUnknownParameterType = "warning"
 
 [tool.pytest.ini_options]
 testpaths = ["tests"]