feat: capture blockers while filing mobile issues (Closes #841)

frontend/index.html

@@ -806,6 +806,15 @@
       <label for="create-issue-due-date">Due date <span class="small">Optional</span>
         <input id="create-issue-due-date" type="date" />
       </label>
+      <section class="create-issue-blockers" aria-labelledby="create-issue-blockers-heading">
+        <strong id="create-issue-blockers-heading">Blocked by <span class="small">Optional · Up to 5 open issues</span></strong>
+        <label for="create-issue-blocker-search">Search open issues
+          <input id="create-issue-blocker-search" type="search" maxlength="80" placeholder="Issue title or key" autocomplete="off" />
+        </label>
+        <div id="create-issue-blocker-results" role="listbox" aria-label="Open issue blocker results" hidden></div>
+        <ul id="create-issue-blocker-selected" aria-label="Selected blockers"></ul>
+        <div id="create-issue-blocker-status" class="small" aria-live="polite">No blockers selected.</div>
+      </section>
       <fieldset class="create-issue-labels" id="create-issue-labels" aria-describedby="create-issue-label-status">
         <legend>Labels <span class="small">Optional</span></legend>
         <div class="small" id="create-issue-label-status" aria-live="polite">Choose a repository to load labels.</div>
@@ -864,6 +873,7 @@
       <div><dt>Title</dt><dd id="issue-filing-review-title"></dd></div>
       <div><dt>Note</dt><dd id="issue-filing-review-body"></dd></div>
       <div><dt>Planning</dt><dd id="issue-filing-review-metadata"></dd></div>
+      <div><dt>Blocked by</dt><dd><ul id="issue-filing-review-blockers"></ul></dd></div>
     </dl>
     <section aria-labelledby="issue-filing-review-evidence-heading">
       <h3 id="issue-filing-review-evidence-heading">Evidence in filing order</h3>