Convert add_purchase.js to TypeScript; drop dead add_edition.js (issue #17)

- Add ts/add_purchase.ts: typed port of add_purchase.js. Replaces getEl with
  document.querySelector; types the search-select:change CustomEvent detail
  (SearchSelectChangeDetail / SearchSelectOption)
- Point add_purchase / edit_purchase views at compiled dist/add_purchase.js
- Delete add_edition.js: no Edition model/view/url/template references it
  (feature was removed; the script was dead)
- Delete the now-superseded add_game.js / add_purchase.js source files
- Tighten test_rendered_pages assertions to the dist/ script paths

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

ts/add_purchase.ts

@@ -0,0 +1,75 @@
+import { disableElementsWhenTrue, onSwap } from "./utils.js";
+
+interface SearchSelectOption {
+  value: string;
+  label: string;
+  data: Record<string, string>;
+}
+
+interface SearchSelectChangeDetail {
+  name: string;
+  values: string[];
+  last: SearchSelectOption | null;
+}
+
+// Switch between a single bundle price and one price per game. The per-game
+// inputs are the selection-fields element; this only sets the policy: the
+// hidden pricing_mode the view reads, the element's "active" flag, and whether
+// the bundle Price field is shown.
+function applyPricingMode(separate: boolean): void {
+  const pricingMode = document.querySelector<HTMLInputElement>("#id_pricing_mode");
+  if (pricingMode) pricingMode.value = separate ? "per_game" : "combined";
+
+  const selectionFields = document.querySelector("selection-fields");
+  if (selectionFields)
+    selectionFields.setAttribute("active", separate ? "true" : "false");
+
+  const priceInput = document.querySelector<HTMLInputElement>("#id_price");
+  if (priceInput) {
+    const wrapper = priceInput.closest("div");
+    if (wrapper) wrapper.classList.toggle("hidden", separate);
+  }
+}
+
+// The games field is a SearchSelect widget (a <div>, not a <select>), so we
+// react to its custom "search-select:change" event instead of syncing a select.
+document.addEventListener("search-select:change", (event) => {
+  const detail = (event as CustomEvent<SearchSelectChangeDetail>).detail;
+  if (detail.name !== "games") return;
+
+  // Auto-fill platform from the clicked option's data-platform.
+  const last = detail.last;
+  const platformId = last && last.data ? last.data.platform : "";
+  if (platformId) {
+    const platformElement = document.querySelector<HTMLInputElement>("#id_platform");
+    if (platformElement) platformElement.value = platformId;
+  }
+
+  // The combined/per-game choice is only meaningful with 2+ games. Reveal the
+  // checkbox there; below the threshold, fall back to a single bundle price.
+  const separateRow = document.querySelector<HTMLElement>("#separate-prices-row");
+  const multipleGames = detail.values.length >= 2;
+  if (separateRow) separateRow.classList.toggle("hidden", !multipleGames);
+  if (!multipleGames) {
+    const checkbox = document.querySelector<HTMLInputElement>("#id_separate_prices");
+    if (checkbox) checkbox.checked = false;
+    applyPricingMode(false);
+  }
+});
+
+onSwap("#id_separate_prices", (checkbox) => {
+  checkbox.addEventListener("change", () =>
+    applyPricingMode((checkbox as HTMLInputElement).checked)
+  );
+});
+
+function setupElementHandlers(): void {
+  disableElementsWhenTrue("#id_type", "game", ["#id_name", "#id_related_game"]);
+}
+
+onSwap("#id_type", (typeSelect) => {
+  setupElementHandlers();
+  typeSelect.addEventListener("change", () => {
+    setupElementHandlers();
+  });
+});