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/main.html

@@ -21,7 +21,7 @@
 <p class="empty">{{if .Entries}}No page{{else}}Empty folder{{end}} — <a href="?edit">[CREATE]</a></p>
 {{end}}
 {{if .Entries}}
-<h2 id="files">Files <button class="btn btn-small" data-companion-reveal hidden title="Open folder in file manager">open</button>{{if .CanEdit}} <button class="btn btn-small" id="view-settings-btn" onclick="openViewSettings()" title="View &amp; sorting" data-view="{{.View}}" data-sort="{{.Sort}}" data-order="{{.Order}}">view</button>{{end}}</h2>
+<h2 id="files">Files <button class="btn btn-small" data-companion-reveal hidden title="Open folder in file manager">open</button>{{if .CanEdit}} <button class="btn btn-small" hx-get="?dialog=view" hx-target="#modal-host" title="View &amp; sorting">view</button>{{end}}</h2>
 {{if eq .View "thumbnail"}}
 <div class="thumb-grid">
     {{range .Entries}}
@@ -44,12 +44,10 @@
     </tbody>
 </table>
 {{end}}
-{{if .CanEdit}}<script src="{{asset "page/view-settings.js"}}"></script>{{end}}
 {{end}}
 {{if or .Content .SpecialContent}}
 <script src="{{asset "page/content.js"}}"></script>
 {{if not .SuppressTOC}}<script src="{{asset "page/toc.js"}}"></script>{{end}}
-<script src="{{asset "page/tasks.js"}}"></script>
 {{end}}
 {{if .Content}}
 <script src="{{asset "page/sections.js"}}"></script>