webui: edit-category modal + dropdown dedupe

Add an "Edit category…" context-menu item and modal that renames a
category and/or changes its save path (Uncategorized: path only).
Filter empty-named categories out of the add/set-category dropdowns so
the stored Uncategorized save-path entry doesn't double the option.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

public/js/api.js

@@ -36,6 +36,8 @@ export const api = {
 
   createCategory: (name, savePath) => jpost('/api/categories', { name, savePath }),
   deleteCategory: (name) => jpost('/api/categories/delete', { name }),
+  editCategory: (name, newName, savePath) =>
+    jpost('/api/categories/edit', { name, newName, savePath }),
   createTag: (name) => jpost('/api/tags', { name }),
   deleteTag: (name) => jpost('/api/tags/delete', { name }),
 

public/js/app.js

@@ -264,6 +264,9 @@ function onSidebarContext(e, type, value, removable) {
   const items = [
     { label: type === 'category' ? 'New category…' : 'New tag…', act: () => (type === 'category' ? openCreateCategory() : openCreateTag()) },
   ];
+  if (type === 'category') {
+    items.push({ label: 'Edit category…', act: () => openEditCategory(value) });
+  }
   if (removable) {
     items.push({ sep: true });
     items.push({ label: `Delete ${type}`, danger: true, act: () => confirmDeleteMeta(type, value) });
@@ -495,7 +498,7 @@ async function confirmDelete(hashes) {
 /* ---------- add torrent modal ---------- */
 function openAddModal() {
   const cats = '<option value="" selected>Uncategorized</option>' +
-    state.meta.categories.map((c) => `<option value="${f.esc(c.name)}">${f.esc(c.name || 'Uncategorized')}</option>`).join('');
+    state.meta.categories.filter((c) => c.name).map((c) => `<option value="${f.esc(c.name)}">${f.esc(c.name)}</option>`).join('');
   const tagOpts = state.meta.tags.map((t) =>
     `<label class="cbdrop-item"><input type="checkbox" value="${f.esc(t)}"><span>${f.esc(t)}</span></label>`).join('');
   openModal('Add torrent', `
@@ -765,7 +768,7 @@ function promptCategory() {
   const cur = state.snapshot?.torrents?.find((t) => t.hash === [...state.selected][0])?.category || '';
   const sel = (v) => (v === cur ? ' selected' : '');
   const opts = `<option value=""${sel('')}>Uncategorized</option>` +
-    state.meta.categories.map((c) => `<option value="${f.esc(c.name)}"${sel(c.name)}>${f.esc(c.name || 'Uncategorized')}</option>`).join('');
+    state.meta.categories.filter((c) => c.name).map((c) => `<option value="${f.esc(c.name)}"${sel(c.name)}>${f.esc(c.name)}</option>`).join('');
   openModal('Set category', `
     <div class="field"><label>Category</label><select id="catSel">${opts}</select></div>
     <p class="dim" style="font-size:12px">Need a new one? Use <b>+</b> next to “Categories” in the sidebar.</p>`,
@@ -795,6 +798,33 @@ function openCreateCategory() {
   setTimeout(() => document.getElementById('catName')?.focus(), 0);
 }
 
+function openEditCategory(value) {
+  const isUncat = value === '';
+  const cur = state.meta.categories.find((c) => c.name === value);
+  const curPath = cur ? (cur.savePath || '') : '';
+  const nameField = isUncat
+    ? `<div class="field"><label>Name</label><input type="text" value="Uncategorized" disabled /></div>`
+    : `<div class="field"><label>Name</label><input type="text" id="catName" value="${f.esc(value)}" /></div>`;
+  openModal('Edit category', `
+    ${nameField}
+    <div class="field"><label>Save path</label>
+      <input type="text" id="catPath" value="${f.esc(curPath)}" placeholder="${f.esc(state.meta.preferences.save_path || '/data/downloads')}" /></div>`,
+    [{ label: 'Cancel', act: closeModal }, {
+      label: 'Save', primary: true, act: async () => {
+        const newName = isUncat ? '' : document.getElementById('catName').value.trim();
+        if (!isUncat && !newName) return closeModal();
+        const savePath = document.getElementById('catPath').value.trim();
+        await api.editCategory(value, newName, savePath);
+        await refreshMeta();
+        if (!isUncat && newName !== value && state.filter.type === 'category' && state.filter.value === value)
+          state.filter = { type: 'category', value: newName };
+        renderView();
+        closeModal();
+      },
+    }]);
+  setTimeout(() => document.getElementById('catName')?.focus(), 0);
+}
+
 function openCreateTag() {
   openModal('New tag', `<div class="field"><label>Name</label><input type="text" id="tagName" placeholder="e.g. seed-2weeks" /></div>`,
     [{ label: 'Cancel', act: closeModal }, {