fix: make FuzzySearch generic to support typed items

- Add SearchableItem base interface for minimum required fields
- Make FuzzySearch class generic with type parameter
- Update all page scripts to use typed FuzzySearch instances
- Fix type casting in calculateScore method

website/src/scripts/pages/instructions.ts

@@ -23,7 +23,7 @@ interface InstructionsData {
 
 const resourceType = 'instruction';
 let allItems: Instruction[] = [];
-let search = new FuzzySearch();
+let search = new FuzzySearch<Instruction>();
 let extensionSelect: Choices;
 let currentFilters = { extensions: [] as string[] };