feat: fill Today from ranked Find Work results (Closes #677)

frontend/index.html

@@ -541,6 +541,8 @@
       <button id="clear-find-work-search" type="button" hidden>Clear</button></div>
       <span id="find-work-match-status" class="small" aria-live="polite"></span>
     </form>
+    <button class="fill-find-work-today" id="fill-find-work-today" type="button"
+      aria-describedby="find-work-selection-status">Fill remaining Today slots</button>
     <div id="find-work-status" class="small" aria-live="assertive">Open Find Work to load available issues.</div>
     <div class="find-work-list" id="find-work-list"></div>
     <button class="find-work-more" id="load-more-available" type="button" hidden>Load more available issues</button>