feat: adds nested query rule

[theodesp]

Description

This PR introduces a new query analysis rule, NestedQueryRule, to the wpgraphql-debug-extensions plugin. This rule is designed to help developers identify and prevent overly nested GraphQL queries, which can lead to performance degradation and increased server load.

Related Issue

Dependant PRs

None.

Type of Change

[ ] ✅ Bug fix (non-breaking change which fixes an issue)

[x] ✨ New feature (non-breaking change which adds functionality)

[ ] 💥 Breaking change (fix or feature that would cause existing functionality to change)

[x] 🧹 Code refactoring (no functional changes)

[ ] 📄 Example update (no functional changes)

[ ] 📝 Documentation update

[ ] 🔍 Performance improvement

[ ] 🧪 Test update

Test Queries and Expected Output

1. Query does not trigger the rule (Simple)

Max depth: 5 (well below the limit of 8)

query {
  posts { # Depth 1
    nodes { # Depth 2
      id
      title
      author { # Depth 3
        node { # Depth 4
          name # Depth 5
        }
      }
    }
  }
}
Expected debugExtensions.nestedQuery Output:

```json
{
  "nestedQuery": {
    "triggered": false,
    "message": "Nested query depth of 5 is within the allowed limit of 8.",
    "details": {
      "maxDepthReached": 5,
      "maxAllowed": 8
    }
  }
}

2. Query triggers the rule (Deeply Nested)

This query exceeds the maximum depth of 8 with a nesting depth of 9.

query {
  posts { # Depth 1
    nodes { # Depth 2
      id
      categories { # Depth 3
        nodes { # Depth 4
          posts { # Depth 5
            nodes { # Depth 6
              author { # Depth 7
                node { # Depth 8
                  posts { # Depth 9
                    nodes {
                      id
                    }
                  }
                }
              }
            }
          }
        }
      }
    }
  }
}

Expected debugExtensions.nestedQuery Output:

{
  "nestedQuery": {
    "triggered": true,
    "message": "Nested query depth of 9 reached or exceeded the configured maximum of 8.",
    "details": {
      "maxDepthReached": 9,
      "maxAllowed": 8
    }
  }
}

3. Query That Does Not Trigger the Rule (With a Fragment)

Max depth: 4 (fragment stays well within limit)

fragment AuthorDetails on Post {
  id
  author { # Depth 3 inside fragment spread
    node { # Depth 4
      name
    }
  }
}

query {
  posts { # Depth 1
    nodes { # Depth 2
      ...AuthorDetails # Spread at depth 3
    }
  }
}

Expected debugExtensions.nestedQuery Output:

{
  "nestedQuery": {
    "triggered": false,
    "message": "Nested query depth of 4 is within the allowed limit of 8.",
    "details": {
      "maxDepthReached": 4,
      "maxAllowed": 8
    }
  }
}

4. Query That Triggers the Rule (With a Fragment)

Max depth: 9 (fragment spread creates over-limit nesting)

fragment DeepAuthorDetails on Post {
  author { # Depth 3 from main query
    node { # Depth 4
      posts { # Depth 5
        nodes { # Depth 6
          author { # Depth 7
            node { # Depth 8
              posts { # Depth 9
                nodes { # Depth 10
                  id   # Depth 11
                }
              }
            }
          }
        }
      }
    }
  }
}

query {
  posts { # Depth 1
    nodes { # Depth 2
      ...DeepAuthorDetails # Spread at depth 2
    }
  }
}

Expected debugExtensions.nestedQuery Output:

{
  "nestedQuery": {
    "triggered": true,
    "message": "Nested query depth of 11 reached or exceeded the configured maximum of 8.",
    "details": {
      "maxDepthReached": 11,
      "maxAllowed": 8
    }
  }
}

Checklist
[x] I have read the CONTRIBUTING document

[x] My code follows the project's coding standards

[x] I have commented my code, particularly in hard-to-understand areas

[ ] I have made corresponding changes to the documentation (if applicable)

[x] My changes generate no new warnings

[x] I have added tests that prove my fix is effective or that my feature works (if applicable)

[ ] Any dependent changes have been highlighted, merged or published

[changeset-bot]

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Latest commit: c77a2ba

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[github-actions]

ℹ️ Download the latest wpgraphql-debug-extensions plugin zip from this PR
(See the 'Artifacts' section at the bottom)

[colinmurphy]

LGTM 🚀 🚀 🚀