fix(e2e): skip token-auth test when no curl CLI is available

The android emulator images ship no curl binary, so minting the gateway
token via popen(curl) read an empty response and the test failed. Probe
for the curl CLI first and report SKIPPED when it is missing.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Author: andinux

test/integration.c

@@ -336,13 +336,29 @@ int integration_network_init(sqlite3 *db, const char *database_id, char *network
 // Fixed, obviously-synthetic user id ("e2e test") used for every minted token.
 #define TOKEN_TEST_USER_ID "e2e7e57e-0000-4000-8000-000000000001"
 
+// Some platforms that run the tests have no curl CLI (e.g. Android emulator images).
+int curl_cli_available (void) {
+#ifdef _WIN32
+    FILE *pipe = popen("curl --version 2>nul", "r");
+#else
+    FILE *pipe = popen("curl --version 2>/dev/null", "r");
+#endif
+    if (!pipe) return 0;
+    char buffer[64];
+    size_t nread = fread(buffer, 1, sizeof(buffer), pipe);
+    pclose(pipe);
+    return nread > 0;
+}
+
 // Mint a user token from the gateway (POST /v2/tokens) via the curl CLI: this binary
 // is built without networking, HTTP lives only in the loaded extension.
-// Returns TEST_SKIPPED when the gateway address or apikey is not configured.
+// Returns TEST_SKIPPED when the gateway address or apikey is not configured,
+// or when there is no curl CLI to mint the token with.
 int fetch_gateway_token (char *token, size_t token_len) {
     const char *gateway = getenv("INTEGRATION_TEST_WEBLITE_ADDRESS");
     const char *apikey = getenv("INTEGRATION_TEST_APIKEY");
     if (!gateway || !*gateway || !apikey || !*apikey) return TEST_SKIPPED;
+    if (!curl_cli_available()) return TEST_SKIPPED;
 
     // expire the token in 24h so repeated runs don't leave live credentials behind
     time_t expires_time = time(NULL) + 24*60*60;