Add post_progress_to_api lightweight telemetry ping

Introduce post_progress_to_api() in misc/api.func — a non-blocking, fire-and-forget curl ping (gated by DIAGNOSTICS and RANDOM_UUID) that updates telemetry status to "configuring". Wire this progress ping into multiple scripts (alpine-install.func, install.func, build.func, core.func) at key milestones (container start, network ready, customization, creation, cleanup) and replace/deduplicate some earlier post_to_api calls. Also update error_handler.func to always report failures immediately via post_update_to_api to ensure failures are captured even before/after container lifecycle.

misc/install.func

@@ -285,6 +285,7 @@ motd_ssh() {
     sed -i "s/#PermitRootLogin prohibit-password/PermitRootLogin yes/g" /etc/ssh/sshd_config
     systemctl restart sshd
   fi
+  post_progress_to_api
 }
 
 # ==============================================================================
@@ -323,4 +324,5 @@ EOF
     chmod 700 /root/.ssh
     chmod 600 /root/.ssh/authorized_keys
   fi
+  post_progress_to_api
 }