Initial CST-Agent: portable Linux/Termux/Windows coding agent.

Vendored sashidown, OpenAI-compatible env (OPENAI_*), and bootstrap scripts.

Co-authored-by: Cursor <cursoragent@cursor.com>

tests/test_json_baseline.c

@@ -0,0 +1,55 @@
+#include "cst_agent.h"
+
+#include <stdio.h>
+#include <string.h>
+
+static int expect(int cond, const char *msg) {
+  if (!cond) {
+    fprintf(stderr, "FAIL: %s\n", msg);
+    return 0;
+  }
+  return 1;
+}
+
+static int test_complete_json(void) {
+  const char *j =
+      "Here is a call {\"name\":\"read_file\",\"arguments\":{\"path\":\"a.c\"}} "
+      "done";
+  cst_json_tool_t t;
+  int ok = cst_json_try_parse_tool(j, strlen(j), &t);
+  int pass = expect(ok == 1, "parse ok");
+  pass &= expect(t.ok == 1, "ok flag");
+  pass &= expect(strcmp(t.name, "read_file") == 0, "name");
+  pass &= expect(strstr(t.arguments_json, "path") != NULL, "args");
+  return pass;
+}
+
+static int test_truncated_json(void) {
+  const char *j = "{\"name\":\"read_file\",\"arguments\":{\"path\":\"a";
+  cst_json_tool_t t;
+  int ok = cst_json_try_parse_tool(j, strlen(j), &t);
+  return expect(ok == 0, "truncated must fail");
+}
+
+static int test_unclosed_brace(void) {
+  const char *j = "{\"name\":\"run_shell\",\"arguments\":{\"cmd\":\"ls\"";
+  cst_json_tool_t t;
+  int ok = cst_json_try_parse_tool(j, strlen(j), &t);
+  return expect(ok == 0, "unclosed brace fails");
+}
+
+int main(void) {
+  int nfail = 0;
+  if (!test_complete_json())
+    nfail++;
+  if (!test_truncated_json())
+    nfail++;
+  if (!test_unclosed_brace())
+    nfail++;
+  if (nfail) {
+    fprintf(stderr, "%d failed\n", nfail);
+    return 1;
+  }
+  printf("test_json_baseline: OK\n");
+  return 0;
+}