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/api.func

@@ -688,6 +688,29 @@ EOF
   POST_TO_API_DONE=true
 }
 
+# ------------------------------------------------------------------------------
+# post_progress_to_api()
+#
+# - Lightweight progress ping from host or container
+# - Updates the existing telemetry record status to "configuring"
+# - Signals that the installation is actively progressing (not stuck)
+# - Fire-and-forget: never blocks or fails the script
+# - Only executes if DIAGNOSTICS=yes and RANDOM_UUID is set
+# - Can be called multiple times safely
+# ------------------------------------------------------------------------------
+post_progress_to_api() {
+  command -v curl &>/dev/null || return 0
+  [[ "${DIAGNOSTICS:-no}" == "no" ]] && return 0
+  [[ -z "${RANDOM_UUID:-}" ]] && return 0
+
+  local app_name="${NSAPP:-${app:-unknown}}"
+  local telemetry_type="${TELEMETRY_TYPE:-lxc}"
+
+  curl -fsS -m 5 -X POST "${TELEMETRY_URL:-https://telemetry.community-scripts.org/telemetry}" \
+    -H "Content-Type: application/json" \
+    -d "{\"random_id\":\"${RANDOM_UUID}\",\"execution_id\":\"${EXECUTION_ID:-${RANDOM_UUID}}\",\"type\":\"${telemetry_type}\",\"nsapp\":\"${app_name}\",\"status\":\"configuring\"}" &>/dev/null || true
+}
+
 # ------------------------------------------------------------------------------
 # post_update_to_api()
 #