chore(web): library-admin inline script moves to admin.ts; rendering guardrail

The library admin page carried an inline <script> block of global
functions (toggleLibraryPanel, openEditModal, openDeleteModal,
openFolderBrowser plus the delete-modal close listener). They move into
the admin Alpine component as typed methods; the page body gains
x-data="admin" and the call sites switch onclick= -> @click.
Behavior unchanged.

Guardrail: make lint-rendering (wired into make test) fails when a
web/src file builds more HTML template literals than its recorded
baseline (web/src/rendering-allowlist.txt, seeded at 18 sites across 9
files post-twin-deletion) or when a .templ file gains an inline script
block. theme_flash_guard.templ is the only sanctioned inline script;
web/src/reader is a sanctioned island.

theme.ts: Array.from(classList) — DOMTokenList spread needs
lib.dom.iterable, which the tsconfig does not include.

web/src/admin.ts

@@ -450,10 +450,86 @@ export {
   stopScanStatusPolling,
 };
 
+// Library admin page helpers (rendering-ownership: these orchestrate htmx
+// swaps and modal visibility on server-rendered DOM; they render nothing).
+function toggleLibraryPanel(btn: HTMLElement): void {
+  const libId = btn.dataset.libId || "";
+  const panel = document.getElementById(`library-panel-${libId}`);
+  if (!panel) return;
+  if (panel.innerHTML.trim() !== "") {
+    panel.innerHTML = "";
+  } else {
+    window.htmx.ajax("GET", `/admin/library/${libId}/panel`, {
+      target: `#library-panel-${libId}`,
+      swap: "innerHTML",
+    });
+  }
+}
+
+function openEditModal(id: string, name: string, description: string): void {
+  const form = document.getElementById("edit-library-form");
+  if (!form) return;
+  form.setAttribute("hx-put", `/admin/library/${id}`);
+  const nameInput = document.getElementById("edit-library-name");
+  if (nameInput) (nameInput as HTMLInputElement).value = name;
+  const descInput = document.getElementById("edit-library-desc");
+  if (descInput) (descInput as HTMLInputElement).value = description;
+  window.htmx.process(form);
+  document.getElementById("edit-library-modal")?.classList.remove("hidden");
+}
+
+function openDeleteModal(id: string, name: string): void {
+  const btn = document.getElementById("delete-library-confirm");
+  if (!btn) return;
+  btn.setAttribute("hx-delete", `/admin/library/${id}`);
+  btn.setAttribute("hx-target", "#libraries-container");
+  btn.setAttribute("hx-swap", "innerHTML");
+  const nameEl = document.getElementById("delete-library-name");
+  if (nameEl) nameEl.textContent = name;
+  window.htmx.process(btn);
+  document.getElementById("delete-library-modal")?.classList.remove("hidden");
+}
+
+function openFolderBrowser(targetInputId: string, libraryId: string): void {
+  const content = document.getElementById("folder-browser-content");
+  if (!content) return;
+  content.setAttribute("hx-get", "/admin/library/browse");
+  content.setAttribute(
+    "hx-vals",
+    JSON.stringify({ target_input: targetInputId, library_id: libraryId }),
+  );
+  content.setAttribute("hx-trigger", "load");
+  window.htmx.process(content);
+  document.getElementById("folder-browser-modal")?.classList.remove("hidden");
+}
+
+// Close the delete-library modal after a successful delete: the htmx swap
+// already removes the deleted row from the libraries list, but the modal
+// lives outside the swapped container and would otherwise stay open.
+function bindDeleteLibraryModalClose(): void {
+  document
+    .getElementById("delete-library-confirm")
+    ?.addEventListener("htmx:afterRequest", function (evt) {
+      const detail = (evt as CustomEvent).detail as { successful?: boolean };
+      if (detail.successful) {
+        document
+          .getElementById("delete-library-modal")
+          ?.classList.add("hidden");
+      }
+    });
+}
+
 Alpine.data("admin", () => ({
+  init() {
+    bindDeleteLibraryModalClose();
+  },
   checkActiveScans,
   hideScanProgress,
   loadWatchStatus,
   scanAllLibraries,
   stopScanStatusPolling,
+  openDeleteModal,
+  openEditModal,
+  openFolderBrowser,
+  toggleLibraryPanel,
 }));