docs: late_resequenced counts held-then-delivered packets, not gaps avoided

Fix the false trailing clause in the udps_stats_t::late_resequenced comment,
move udps_held_t from the tunable-limits section to internal-state next to
udps_slot_t, and add braces to three braceless if bodies to match house style.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

deps/udpsclient/udps_client.c

@@ -38,15 +38,6 @@
 /** Total bytes the reorder ring may hold, so a fast stream cannot grow it without bound. */
 #define UDPS_REORDER_BYTES (4u * 1024u * 1024u)
 
-typedef struct {
-    uint8_t *buf;       /**< owned; grown on demand to the payload's length */
-    size_t   cap;
-    size_t   len;
-    uint32_t counter;
-    double   recv_time;
-    int      used;
-} udps_held_t;
-
 /** Concurrent in-flight reassemblies. The server interleaves at most a couple. */
 #define UDPS_MAX_SLOTS 4
 
@@ -165,6 +156,16 @@ typedef struct {
     double   first_seen;
 } udps_slot_t;
 
+/** One slot in the reorder ring: a raw payload held until its counter is next. */
+typedef struct {
+    uint8_t *buf;       /**< owned; grown on demand to the payload's length */
+    size_t   cap;
+    size_t   len;
+    uint32_t counter;
+    double   recv_time;
+    int      used;
+} udps_held_t;
+
 struct udps_client {
     udps_client_config_t cfg;
     /* Owned copies: the caller's strings need not outlive the create call. */
@@ -747,7 +748,7 @@ static int order_data(udps_client_t *c, const uint8_t *pl, size_t len,
     if (delta == 0) {
         int rc = deliver_data(c, pl, len, counter, recv_time, 0u, 0);
         c->next_counter = counter + 1u;
-        if (rc == 0) rc = drain_held(c, 0u);
+        if (rc == 0) { rc = drain_held(c, 0u); }
         return rc;
     }
     if (delta > 0) {
@@ -1364,8 +1365,8 @@ int udps_client_poll(udps_client_t *c, int timeout_ms) {
      * the next arrival is 100 ms away, which is five times the whole budget. */
     if (c->gap_deadline > 0.0) {
         double left = c->gap_deadline - now_wall();
-        if (left < 0.0) left = 0.0;
+        if (left < 0.0) { left = 0.0; }
-        if (left < budget) budget = left;
+        if (left < budget) { budget = left; }
     }
 
     FD_ZERO(&rset);

deps/udpsclient/udps_client.h

@@ -188,8 +188,12 @@ typedef struct {
      */
     uint64_t stale_packets;
     /**
-     * DATA packets that arrived out of order and were put *back* in order inside
+     * DATA packets that were held waiting for an earlier counter and subsequently
-     * the reorder window, so the consumer never saw a gap for them.
+     * delivered via @c drain_held().  This includes a packet released by the
+     * reorder window expiring: that packet arrives alongside a non-zero @c lost
+     * and therefore alongside a gap, so @c late_resequenced is not by itself a
+     * count of gaps avoided.  Compare @c late_delivered, which counts packets
+     * that lost the race past an already-expired window entirely.
      */
     uint64_t late_resequenced;
     /**