Capture Trends data into extension storage

[davis118]

Description

Implements issue #117.
Pulls Skedge's planner-v2 attribute from localStorage,then filters for classes with a selected section. Finally, place into Plasmo storage, in the following format, on page load and localStorage update.

export interface ClassData {
  query: {
    prefix: string;
    number: string;
    profFirst?: string;
    profLast?: string;
    sectionNumbers?: string[];
  };
  semester: string;
}

Testing

• Compiles and passes lint and format
• Plasmo Storage stays in sync while I checked some boxes on My Planner
• Classes with non-selected sections are correctly filtered out

AI Disclosure

Used AI to understand how Plasmo js worlds work, and how the extension environment differs from the regular webpage environment.

Checklist

• Create this PR
• Perform final self-review