hub v0.3.2: Show Hub version in page footers

Add hubVersion template function via closure in web.New(). Version is
passed from main.go (set via ldflags at build time) and displayed in
the footer of all 6 page templates.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

hub/internal/web/templates/config_form.html

@@ -142,7 +142,7 @@
         </form>
 
         <footer>
-            <p>Felhom Hub — Configuration Management</p>
+            <p>Felhom Hub {{hubVersion}} — Configuration Management</p>
         </footer>
     </div>
 </body>