Replace ClientFindServers with unified Client, use trust store directories

Replace the single-purpose ClientFindServers program with a unified Client
that supports three operations via CLI: find-servers, get-endpoints, and
read-time.  This simplifies the architecture by using one client binary with
a single config file instead of a monolithic program that did everything in
one run.

Split the ServerRegister config into separate server and client config files
so the LDS-registration credentials are isolated from the server's own
settings.  The discovery URL moves from config to a CLI argument.

Replace repeated trustList config entries with a single trustStore directory
path.  Each program now points to a directory under certs/trust/ containing
.der files, so adding or removing trust is a file-copy operation rather than
editing every config file.  Add loadTrustStore()/freeTrustStore() to
common.c and remove the now-unused configGetAll() from the config parser.

Simplify the test matrix from 6 to 4 cases (security and auth are
orthogonal, so the full 3x2 matrix is unnecessary).  Update run_test.sh to
invoke the new Client three times and use port-polling instead of sleep.

1 files changed, 25 insertions, 0 deletions

diff --git a/src/common.h b/src/common.h
index e8c0c78..7290181 100644
--- a/src/common.h
+++ b/src/common.h
@@ -13,6 +13,8 @@
 #include <open62541/server.h>
 #include <open62541/types.h>
 
+#include <stddef.h>
+
 /**
  * @brief Loads a DER-encoded certificate or key file into a UA_ByteString.
  *
@@ -22,6 +24,29 @@
 UA_ByteString loadFile (const char *const path);
 
 /**
+ * @brief Collects all *.der file paths from a trust store directory.
+ *
+ * Opens the directory, finds every file ending in ".der", and builds
+ * heap-allocated full paths (dirPath/filename).  The caller must free
+ * the result with freeTrustStore().
+ *
+ * @param dirPath   Path to the trust store directory.
+ * @param outPaths  Output: heap-allocated array of heap-allocated strings.
+ *                  Set to NULL when the directory is empty.
+ * @param outSize   Output: number of entries in outPaths.
+ * @return 0 on success, -1 on error (logged via UA_LOG_ERROR).
+ */
+int loadTrustStore (const char *dirPath, char ***outPaths, size_t *outSize);
+
+/**
+ * @brief Frees the array returned by loadTrustStore().
+ *
+ * @param paths  The array of strings (may be NULL).
+ * @param size   Number of entries.
+ */
+void freeTrustStore (char **paths, size_t size);
+
+/**
  * @brief Creates a UA_Server configured with security policies and encryption.
  *
  * The server is initialized with the specified port, certificate, private key,