feat(css_semantic): implement rule hierarchy tracking and enhance rule lookup

[togami2864]

Summary

This PR improves the CSS semantic model by implementing a more efficient rule hierarchy tracking system and improving rule lookup.

get_rule_by_range

I added a new public API, get_rule_by_range to the model that can be used in lint rules.

.foo{
  color: red;
  .bar {
    color: blue;
    font-size: 20px;
    .baz {
      color: pink
    }
  }
}

let model = ctx.model();

let range = node.range(); // Consider node as `color: blue` in `.bar`

// Get the rule containing the given range
let rule = model.get_rule_by_range(range);

// See Selectors 
for selector in &rule.selectors {
    // Work with selectors
}

// See other declarations in the same scope
for declaration in &rule.declarations {
    // Work with declarations
}

// Access parent and child rules
if let Some(parent_id) = rule.parent_id {
    let parent_rule = model.get_rule_by_id(parent_id);
    // Work with parent rule
}

for child_id in &rule.child_ids {
    let child_rule = model.get_rule_by_id(*child_id);
    // Work with child rules
}

Test Plan

CI should pass

[chansuke]

Thank you for your work and LGTM now