feat: introduce post resource with full CRUD operations and generation linking.

models/Post.py

@@ -0,0 +1,23 @@
+from datetime import datetime, timezone, UTC
+from typing import Optional, List
+from pydantic import BaseModel, Field, model_validator
+
+
+class Post(BaseModel):
+    id: Optional[str] = None
+    date: datetime
+    topic: str
+    generation_ids: List[str] = Field(default_factory=list)
+    project_id: Optional[str] = None
+    created_by: str
+    is_deleted: bool = False
+    created_at: datetime = Field(default_factory=lambda: datetime.now(UTC))
+    updated_at: datetime = Field(default_factory=lambda: datetime.now(UTC))
+
+    @model_validator(mode="after")
+    def ensure_tz_aware(self):
+        for field in ("date", "created_at", "updated_at"):
+            val = getattr(self, field)
+            if val is not None and val.tzinfo is None:
+                setattr(self, field, val.replace(tzinfo=timezone.utc))
+        return self