List format templates

curl --request GET \
  --url https://api.case.dev/format/v1/templates \
  --header 'Authorization: Bearer <token>'

{
  "templates": [
    {
      "id": "tmpl_abc123",
      "name": "NDA Template",
      "description": "Standard non-disclosure agreement template",
      "type": "contract",
      "variables": [
        "party1",
        "party2",
        "effectiveDate",
        "jurisdiction"
      ],
      "tags": [
        "confidentiality",
        "standard"
      ],
      "usageCount": 42,
      "createdAt": "2024-01-15T10:30:00Z"
    },
    {
      "id": "tmpl_def456",
      "name": "Motion to Dismiss",
      "description": "Template for filing motion to dismiss",
      "type": "pleading",
      "variables": [
        "court",
        "case_number",
        "plaintiff",
        "defendant"
      ],
      "tags": [
        "motion",
        "civil"
      ],
      "usageCount": 18,
      "createdAt": "2024-01-10T14:20:00Z"
    }
  ]
}