Remove the working screenshots and name the page after the service

Three things found in the check before a release. A directory of
screenshots taken while working on the interface had been committed; it
is removed and ignored, because it is a working note rather than part of
the service. Two branches kept pointing at the history from before the
licence changed, which is the only place that history was still reachable;
they are gone. The page title still named the service the way it was named
before it became apsis-book.

The binary was checked from an empty directory with no content tree and no
frontend build beside it: it serves every route from what it carries.

.gitignore

@@ -18,3 +18,7 @@
 # Session exports dropped into the project directory by tooling that runs
 # alongside it. They are large and unrelated to the service.
 apsis-book.html
+
+# Diagnostics dropped beside the project while working on it, such as the
+# screenshots of a page under inspection.
+/tmp

frontend/index.html

@@ -8,7 +8,7 @@
       name="description"
       content="Web interface for the ApsisRS computational kernels: concept documentation, a knowledge graph, the interface documentation, and online tools."
     />
-    <title>ApsisRS web service</title>
+    <title>apsis-book — ApsisRS</title>
   </head>
   <body>
     <div id="app"></div>