Fix/issue 27 server side sorting

[saesarandom]

Summary of Changes:

• Database: Added dynamic ORDER BY handling (level, name, life, mana) in getFilteredCharacters() prior to pagination LIMIT/OFFSET.
• API Route: Extracted sortBy & sortOrder query params in /api/characters.
• Frontend API: Passed sort parameters through charactersAPI.getCharacters().
• CharacterTable: Configured manualSorting: true, sorting state, and onSortingChange handler to refetch page 1 with global sorting when column headers are clicked.

[ChaseBianchi]

rebase this on the latest from main

[ChaseBianchi]

Let’s make the table’s default sort explicit. With the current code, no active sort produces sortBy=undefined but sortOrder="asc". The initial page is level-descending, while later pagination requests become level-ascending. Defaulting to level/desc keeps every page consistently ordered:

const sortBy = activeSort?.id ?? "level";
const sortOrder = activeSort
  ? activeSort.desc
    ? "desc"
    : "asc"
  : "desc";

[ChaseBianchi]

CharacterTable can send sortBy="highestSkLevel", but none of the branches above handle it, so clicking that column currently falls back to sorting by character level. Let's add this branch before the ordering block ends:

} else if (filter.sortBy === "highestSkLevel") {
  orderByClause = `
    (C.full_response_json->'realSkills'->0->>'level')::int
      ${orderDirection}
      NULLS LAST,
    C.character_db_id DESC
  `;
}

[ChaseBianchi]

Mantine React Table enables multi-column sorting by default, but this implementation only sends sorting[0] to the API. Shift-clicking another sortable column therefore displays multiple sort indicators while the server ignores every key after the first. Please set enableMultiSort: false, or extend the API to support all selected keys.