add user texts and text detail pages

new /texts page lets a user manage their own texts (list +
create form linking to /texts/{id}); /texts/{id} reuses
text.js for the node tree, with a back link to /texts. home
gains a 'My texts' link in the header. the admin texts page
now sources its cross-user list from /api/texts/all.

views/templates/home.php

@@ -11,6 +11,9 @@
         <div class="site-header-inner">
             <h1>Home</h1>
             <div class="cluster">
+                <a class="btn btn-secondary" href="/texts" id="manage-texts">
+                    My texts
+                </a>
                 <a class="btn btn-secondary" href="/today">
                     Today's schedule
                 </a>