Improve templates so that more than one can apply to a policy

**Job Story**

When _working with a policy that requires multiple standard forms (e.g., Project Description, Monitoring Report), each with their own versions (e.g., v5a, v5b)_, I want _to apply more than one schema template to a single policy_, so I can _maintain separate, properly-scoped templates per form type/version instead of consolidating all schemas into one large "guardian template."_

**Acceptance Criteria**

* A policy can have more than one schema template applied to it at the same time
* Each template can represent a single, distinct form type (e.g., VCS Project Description v5a, VCS Project Description v5b, VCS Monitoring Report v5a, VCS Monitoring Report v5b) rather than requiring consolidation into one combined template
* Users can select and manage which templates are applied to a given policy

**Artifacts & Considerations**

* Current limitation: schema template enforces a max of one template per policy
* Standard practice: templates should map 1:1 to form types/versions (e.g., VCS Project Description v5a and v5b are distinct templates, not merged)