Nomad changes

docs/snippets/c/plugins/plugin_validator.md

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+```c title="C"
+#include <kreuzberg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+/*
+ * Minimal Validator skeleton: implements the required `validate` function
+ * and the optional `priority` and `should_validate` hooks via the C vtable.
+ */
+
+static char *dup_cstr(const char *s) {
+    size_t len = strlen(s);
+    char *out = (char *)malloc(len + 1);
+    if (out) {
+        memcpy(out, s, len + 1);
+    }
+    return out;
+}
+
+static int32_t validate_fn(
+    const void *user_data,
+    const char *result,
+    const char *config,
+    char **out_error
+) {
+    (void)user_data;
+    (void)config;
+
+    /* Reject results whose serialised form contains a clearly forbidden token. */
+    if (strstr(result, "FORBIDDEN") != NULL) {
+        *out_error = dup_cstr("Content contains forbidden token");
+        return 1;
+    }
+    return 0;
+}
+
+static int32_t should_validate_fn(
+    const void *user_data,
+    const char *result,
+    const char *config
+) {
+    (void)user_data;
+    (void)result;
+    (void)config;
+    return 1;  /* always run */
+}
+
+static int32_t priority_fn(const void *user_data) {
+    (void)user_data;
+    return 50;
+}
+
+int main(void) {
+    KREUZBERGKreuzbergValidatorVTable vtable = {0};
+    vtable.validate = validate_fn;
+    vtable.should_validate = should_validate_fn;
+    vtable.priority = priority_fn;
+
+    char *err = NULL;
+    int32_t rc = kreuzberg_register_validator(
+        "forbidden-token-validator",
+        vtable,
+        NULL,
+        &err
+    );
+    if (rc != 0) {
+        fprintf(stderr, "register validator failed: %s\n", err ? err : "(no detail)");
+        kreuzberg_free_string(err);
+        return 1;
+    }
+
+    printf("forbidden-token-validator registered\n");
+    return 0;
+}
+```