Added functions to fetch requirements from db.

Added functionality to create requirements on page

backend/src/models.py

@@ -1,4 +1,5 @@
 from typing import Optional, List
+from datetime import datetime
 from pydantic import BaseModel, SecretStr
 
 
@@ -35,3 +36,84 @@ class GroupResponse(BaseModel):
 class GroupListResponse(BaseModel):
     """Response schema for list of groups."""
     groups: List[GroupResponse]
+
+
+# Tag schemas
+class TagResponse(BaseModel):
+    """Response schema for a single tag."""
+    id: int
+    tag_code: str
+    tag_description: str
+
+    class Config:
+        from_attributes = True
+
+
+class TagListResponse(BaseModel):
+    """Response schema for list of tags."""
+    tags: List[TagResponse]
+
+
+# Priority schemas
+class PriorityResponse(BaseModel):
+    """Response schema for a priority."""
+    id: int
+    priority_name: str
+    priority_num: int
+
+    class Config:
+        from_attributes = True
+
+
+# Validation schemas
+class ValidationResponse(BaseModel):
+    """Response schema for a validation."""
+    id: int
+    status_name: str
+    req_version_snapshot: int
+    comment: Optional[str] = None
+    created_at: Optional[datetime] = None
+
+    class Config:
+        from_attributes = True
+
+
+# Requirement schemas
+class RequirementResponse(BaseModel):
+    """Response schema for a single requirement."""
+    id: int
+    req_name: str
+    req_desc: Optional[str] = None
+    version: int
+    created_at: Optional[datetime] = None
+    updated_at: Optional[datetime] = None
+    tag: TagResponse
+    priority: Optional[PriorityResponse] = None
+    groups: List[GroupResponse] = []
+    validation_status: Optional[str] = None  # Computed from latest validation
+
+    class Config:
+        from_attributes = True
+
+
+class RequirementListResponse(BaseModel):
+    """Response schema for list of requirements."""
+    requirements: List[RequirementResponse]
+
+
+class RequirementCreateRequest(BaseModel):
+    """Request schema for creating a requirement."""
+    tag_id: int
+    req_name: str
+    req_desc: Optional[str] = None
+    priority_id: Optional[int] = None
+    group_ids: Optional[List[int]] = None
+
+
+class RequirementUpdateRequest(BaseModel):
+    """Request schema for updating a requirement."""
+    req_name: Optional[str] = None
+    req_desc: Optional[str] = None
+    tag_id: Optional[int] = None
+    priority_id: Optional[int] = None
+    group_ids: Optional[List[int]] = None