fix: add retry to initial installing POST (post_to_api / post_to_api_vm)

The initial 'installing' record MUST exist for all subsequent status
updates to succeed. Previously this was fire-and-forget with no retry,
so timeouts/503s silently dropped ~50% of installations.

Both post_to_api (LXC) and post_to_api_vm now retry up to 3 times
with 1s delay between attempts. Also captures HTTP response code to
detect failures instead of using curl -f (silent fail).

Author: MickLesk

misc/api.func

@@ -687,18 +687,23 @@ EOF
   [[ "${DEV_MODE:-}" == "true" ]] && echo "[DEBUG] Sending to: $TELEMETRY_URL" >&2
   [[ "${DEV_MODE:-}" == "true" ]] && echo "[DEBUG] Payload: $JSON_PAYLOAD" >&2
 
-  # Fire-and-forget: never block, never fail
-  local http_code
-  if [[ "${DEV_MODE:-}" == "true" ]]; then
-    http_code=$(curl -sS -w "%{http_code}" -m "${TELEMETRY_TIMEOUT}" -X POST "${TELEMETRY_URL}" \
-      -H "Content-Type: application/json" \
-      -d "$JSON_PAYLOAD" -o /dev/stderr 2>&1) || true
-    echo "[DEBUG] HTTP response code: $http_code" >&2
-  else
-    curl -fsS -m "${TELEMETRY_TIMEOUT}" -X POST "${TELEMETRY_URL}" \
-      -H "Content-Type: application/json" \
-      -d "$JSON_PAYLOAD" &>/dev/null || true
-  fi
+  # Send initial "installing" record with retry.
+  # This record MUST exist for all subsequent updates to succeed.
+  local http_code="" attempt
+  for attempt in 1 2 3; do
+    if [[ "${DEV_MODE:-}" == "true" ]]; then
+      http_code=$(curl -sS -w "%{http_code}" -m "${TELEMETRY_TIMEOUT}" -X POST "${TELEMETRY_URL}" \
+        -H "Content-Type: application/json" \
+        -d "$JSON_PAYLOAD" -o /dev/stderr 2>&1) || http_code="000"
+      echo "[DEBUG] post_to_api attempt $attempt HTTP=$http_code" >&2
+    else
+      http_code=$(curl -sS -w "%{http_code}" -m "${TELEMETRY_TIMEOUT}" -X POST "${TELEMETRY_URL}" \
+        -H "Content-Type: application/json" \
+        -d "$JSON_PAYLOAD" -o /dev/null 2>/dev/null) || http_code="000"
+    fi
+    [[ "$http_code" =~ ^2[0-9]{2}$ ]] && break
+    [[ "$attempt" -lt 3 ]] && sleep 1
+  done
 
   POST_TO_API_DONE=true
 }
@@ -789,10 +794,15 @@ post_to_api_vm() {
 EOF
   )
 
-  # Fire-and-forget: never block, never fail
-  curl -fsS -m "${TELEMETRY_TIMEOUT}" -X POST "${TELEMETRY_URL}" \
-    -H "Content-Type: application/json" \
-    -d "$JSON_PAYLOAD" &>/dev/null || true
+  # Send initial "installing" record with retry (must succeed for updates to work)
+  local http_code="" attempt
+  for attempt in 1 2 3; do
+    http_code=$(curl -sS -w "%{http_code}" -m "${TELEMETRY_TIMEOUT}" -X POST "${TELEMETRY_URL}" \
+      -H "Content-Type: application/json" \
+      -d "$JSON_PAYLOAD" -o /dev/null 2>/dev/null) || http_code="000"
+    [[ "$http_code" =~ ^2[0-9]{2}$ ]] && break
+    [[ "$attempt" -lt 3 ]] && sleep 1
+  done
 
   POST_TO_API_DONE=true
 }