Toggle tasks and edit view settings via htmx

Task checkboxes post themselves (hx-post="?toggle=N") and flip back when
the save fails, replacing tasks.js. View settings are a server-rendered
form dialog with real radios and a select, replacing view-settings.js;
with that, postReplace has no callers left.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

assets/page/actions.js

@@ -3,40 +3,6 @@ function encodePickedPath(p) {
     return '/' + p.replace(/^\/+/, '').split('/').map(encodeURIComponent).join('/');
 }
 
-// postReplace POSTs to action with the optional form body, then loads target
-// into the current history entry — so the action and its result occupy one
-// entry instead of two, and back-navigation skips past the stale pre-mutation
-// snapshot in bfcache. body may be null for empty POSTs.
-//
-// We can't just call window.location.replace(target): when target differs from
-// the current URL only by fragment, the browser updates the URL bar without
-// re-fetching, so a server-side mutation wouldn't be reflected. Instead,
-// rewrite the current entry's URL via history.replaceState, then reload — the
-// reload always re-fetches and preserves the (new) URL including its fragment.
-function navigateReplace(target) {
-    window.history.replaceState(null, '', target);
-    window.location.reload();
-}
-
-function postReplace(action, body, target) {
-    var init = { method: 'POST', redirect: 'manual' };
-    if (body) {
-        init.headers = { 'Content-Type': 'application/x-www-form-urlencoded' };
-        init.body = body;
-    }
-    fetch(action, init).then(function (res) {
-        if (res.type === 'opaqueredirect' || res.ok) {
-            navigateReplace(target);
-            return;
-        }
-        return res.text().then(function (msg) {
-            alert(msg || ('Request failed (' + res.status + ')'));
-        });
-    }).catch(function () {
-        alert('Network error');
-    });
-}
-
 function promptPageName(title, initial, confirmLabel, onName) {
     var input = document.createElement('input');
     input.type = 'text';