feat: add load_primary_config(), myconf_fini(); remove static cf global from myconf.c

- load_primary_config(): resolves conf/current, reads raw bytes, computes
  SHA-256 tag, decodes Cap'n Proto via load_cluster_config_from_file(),
  checks reserved names, sets config_generation, checks staleness
- myconf_fini(): frees conffile and cluster_config (calls free_ClusterConfig)
- Remove static cf global from myconf.c; get_default_conf() now uses a
  local struct cluster_configuration* via load_cluster_config()
- Add load_primary_config_for_test() under XCE_TESTING in config_repl.c
  to test path resolution without triggering FATAL
- Add xce/cluster_def.h include to config_repl.c and test_config_repl.c
  so cluster_t is complete when XCE_TESTING is active
- TDD: test_load_primary_config_missing_returns_error passes (18/18)

src/controller/myconf.c

@@ -1,9 +1,15 @@
+#define _GNU_SOURCE
 #include <errno.h>
+#include <inttypes.h>
+#include <openssl/sha.h>
+#include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <tlog.h>
 
+#include "byteorder.h"
+#include "config_repl.h"
 #include "configobj.h"
 #include "controller.capnp.h"
 #include "myconf.h"
@@ -131,12 +137,10 @@ int load_cluster_config(cluster_t*                     c,
     return 0;
 }
 
-static struct cluster_configuration* cf = NULL;
-
 cluster_config_t* get_default_conf(void* cl)
 {
-    cluster_config_t* c;
-    cluster_t*        cls = (cluster_t*)cl;
+    struct cluster_configuration* cf = NULL;
+    cluster_t*                    cls = (cluster_t*)cl;
 
     load_cluster_config(cls, &cf);
     if (cf == NULL) {
@@ -144,7 +148,109 @@ cluster_config_t* get_default_conf(void* cl)
         return NULL;
     }
 
-    c = cf->cluster;
-
-    return c;
+    return cf->cluster;
+}
+
+/* ── load_primary_config ────────────────────────── */
+
+int load_primary_config(cluster_t *c)
+{
+    myconf_t *myconf = c->myconf;
+
+    /* Build conf dir path: <workdir>/<name> */
+    char conf_dir[4096];
+    snprintf(conf_dir, sizeof(conf_dir), "%s/%s", myconf->workdir, myconf->name);
+
+    /* Resolve conf/current → versioned filename */
+    char fname[256] = {0};
+    int rc = conf_read_current_filename(conf_dir, fname, sizeof(fname));
+    if (rc != 0) {
+        FATAL("Primary has no config at '%s/conf/current' (rc=%d) — "
+              "provision the config before starting",
+              conf_dir, rc);
+        return -ENOENT;
+    }
+
+    /* Heap-allocate conffile so it survives past this stack frame */
+    free(myconf->conffile);
+    myconf->conffile = NULL;
+    if (asprintf(&myconf->conffile, "%s/conf/%s", conf_dir, fname) < 0)
+        return -ENOMEM;
+
+    /* Read raw bytes and check size */
+    uint8_t *bytes = NULL;
+    size_t   blen  = 0;
+    rc = conf_read_raw(myconf->conffile, &bytes, &blen);
+    if (rc != 0) {
+        FATAL("Primary config '%s' unreadable: %d", myconf->conffile, rc);
+        free(myconf->conffile);
+        myconf->conffile = NULL;
+        return rc;
+    }
+
+    /* Compute and cache SHA-256 */
+    SHA256(bytes, blen, myconf->config_sha256);
+    uint64_t tag;
+    memcpy(&tag, myconf->config_sha256, 8);
+    myconf->config_version_tag = be64toh(tag);
+
+    /* Decode Cap'n Proto directly into myconf->cluster_config */
+    rc = load_cluster_config_from_file(myconf->conffile, &myconf->cluster_config);
+    if (rc != 0) {
+        FATAL("Primary config '%s' failed Cap'n Proto decode: %d",
+              myconf->conffile, rc);
+        free(bytes);
+        free(myconf->conffile);
+        myconf->conffile = NULL;
+        return rc;
+    }
+
+    if (myconf->cluster_config == NULL) {
+        FATAL("Primary config '%s' decoded to NULL", myconf->conffile);
+        free(bytes);
+        free(myconf->conffile);
+        myconf->conffile = NULL;
+        return -EINVAL;
+    }
+
+    free(bytes);
+
+    fill_default_cluster_config(myconf->cluster_config);
+
+    /* Check for reserved lost_and_found name */
+    if (config_contains_reserved_name(myconf->cluster_config)) {
+        FATAL("Config '%s' contains reserved name 'lost_and_found'",
+              myconf->conffile);
+        return -EINVAL;
+    }
+
+    /* Default generation to 1 if not set */
+    if (myconf->cluster_config->config_generation == 0)
+        myconf->cluster_config->config_generation = 1;
+    myconf->config_generation = myconf->cluster_config->config_generation;
+
+    /* Check staleness */
+    myconf->conf_stale = conf_check_stale(conf_dir, myconf->conf_stale_timeout);
+    if (myconf->conf_stale)
+        WARN("Primary config appears stale (age > %lds)",
+             (long)myconf->conf_stale_timeout);
+
+    INFO("Primary config loaded: tag=%016" PRIx64 " gen=%" PRIu64,
+         myconf->config_version_tag, myconf->config_generation);
+    return 0;
+}
+
+/* ── myconf_fini ────────────────────────────────── */
+
+void myconf_fini(myconf_t *myconf)
+{
+    if (!myconf)
+        return;
+    free(myconf->conffile);
+    myconf->conffile = NULL;
+    if (myconf->cluster_config) {
+        free_ClusterConfig(myconf->cluster_config);
+        free(myconf->cluster_config);
+        myconf->cluster_config = NULL;
+    }
 }