Function validate_scope 

pub fn validate_scope(scope: &str) -> Result<(), CoercionError>

Validate a scope value for semantic search.

Arguments

• scope - The scope string to validate

Valid Values

• session: Search within a specific session (requires scope_id)
• workspace: Search within a workspace (requires scope_id)
• global: Search across all data (default)

Returns

• Ok(()) if the scope is valid
• Err(CoercionError) with helpful message if invalid