feat: add authentication for OSS (#167)

* feat: add authentication for OSS

Fixes #157 and #156

* fix: fix token generation

* fix: limit fastapi workers to 1

api/schemas/auth.py

@@ -0,0 +1,31 @@
+from pydantic import BaseModel, EmailStr, field_validator
+
+
+class SignupRequest(BaseModel):
+    email: EmailStr
+    password: str
+    name: str | None = None
+
+    @field_validator("password")
+    @classmethod
+    def password_min_length(cls, v: str) -> str:
+        if len(v) < 8:
+            raise ValueError("Password must be at least 8 characters")
+        return v
+
+
+class LoginRequest(BaseModel):
+    email: EmailStr
+    password: str
+
+
+class UserResponse(BaseModel):
+    id: int
+    email: str | None
+    name: str | None = None
+    organization_id: int | None = None
+
+
+class AuthResponse(BaseModel):
+    token: str
+    user: UserResponse