feat(cli): rsync short-option clustering and inline/attached values (#285)

Implement rsync 3.4.1 client-CLI parity:
- cluster boolean shorts (-av, -aAX, -rlpt) and accept attached values
  (-B1048576, -essh, -Mfoo); add the -r, -b, -L and -B short aliases
  (-r is a faithful no-op since FastSync is always recursive)
- stop OPT_NOOP (-s/--secluded-args, -r/--recursive) from swallowing the
  next argv
- add inline --opt=value for every value-taking long option, including
  --exclude/--include/--exclude-from/--include-from/--log-file (#291)
- accept --port on the server CLI in addition to -p (#296)
- reject unknown flags naming the flag and stating it is unsupported

Unit tests cover clustering, attached/inline values, the OPT_NOOP
argument-consumption fix and rejected shorts.

src/server/server.c

@@ -1051,7 +1051,7 @@ static void print_server_usage(void) {
   printf("  --early-input=FILE  Second credential store layered over\n");
   printf("                      --password-file (same format); usually a secrets-\n");
   printf("                      manager/process-substitution file.  Requires --daemon\n");
-  printf("  -p <port>           TCP port (default: 8080, range: 1-65535)\n");
+  printf("  -p, --port <port>   TCP port (default: 8080, range: 1-65535)\n");
   printf("  --tls               Enable TLS encryption\n");
   printf("  --cert <path>       TLS certificate file (PEM)\n");
   printf("  --key <path>        TLS private key file (PEM)\n");

src/server/server_cli.c

@@ -192,14 +192,20 @@ int server_cli_parse(int argc, char* argv[], ServerCliOptions* opts, char* err,
         inline_value = argv[++i];
       }
       opts->iconv_spec = inline_value;
-    } else if (arg_is(argv[i], "-p")) {
-      if (i + 1 >= argc) {
-        set_error(err, err_size, "missing argument for -p");
-        return -1;
+    } else if (arg_is(argv[i], "-p") || arg_has_value(argv[i], "--port", &inline_value)) {
+      if (inline_value) {
+        opts->port_set = true;
+        if (parse_port_arg(inline_value, &opts->port, err, err_size) != 0)
+          return -1;
+      } else {
+        if (i + 1 >= argc) {
+          set_error(err, err_size, "missing argument for %s", argv[i]);
+          return -1;
+        }
+        opts->port_set = true;
+        if (parse_port_arg(argv[++i], &opts->port, err, err_size) != 0)
+          return -1;
       }
-      opts->port_set = true;
-      if (parse_port_arg(argv[++i], &opts->port, err, err_size) != 0)
-        return -1;
     } else {
       if (arg_has_value(argv[i], "--config", &inline_value)) {
         if (!inline_value) {