Refactor backend to SQLModel; reset schema; add Company OS endpoints

backend/app/models/work.py

@@ -0,0 +1,34 @@
+from __future__ import annotations
+
+from datetime import datetime
+
+from sqlmodel import Field, SQLModel
+
+
+class Task(SQLModel, table=True):
+    __tablename__ = "tasks"
+
+    id: int | None = Field(default=None, primary_key=True)
+
+    project_id: int = Field(foreign_key="projects.id", index=True)
+    title: str
+    description: str | None = None
+
+    status: str = Field(default="backlog", index=True)
+
+    assignee_employee_id: int | None = Field(default=None, foreign_key="employees.id")
+    reviewer_employee_id: int | None = Field(default=None, foreign_key="employees.id")
+    created_by_employee_id: int | None = Field(default=None, foreign_key="employees.id")
+
+    created_at: datetime = Field(default_factory=datetime.utcnow)
+    updated_at: datetime = Field(default_factory=datetime.utcnow)
+
+
+class TaskComment(SQLModel, table=True):
+    __tablename__ = "task_comments"
+
+    id: int | None = Field(default=None, primary_key=True)
+    task_id: int = Field(foreign_key="tasks.id", index=True)
+    author_employee_id: int | None = Field(default=None, foreign_key="employees.id")
+    body: str
+    created_at: datetime = Field(default_factory=datetime.utcnow)