string/memmgr: address Copilot review feedback on #4360

furi/core/string.c (furi_string_cat_vprintf):
The retry condition used >= which fired one extra vsnprintf when the
formatted output fit exactly into the reserved capacity (NUL byte
included). vsnprintf only truncates when size + 1 > buffer; change
the predicate to match.

furi/core/memmgr.c (realloc):
Drop the unreachable NULL-guard around the copy/free. pvPortMalloc()
calls furi_check(pvReturn, ...) on OOM (memmgr_heap.c:466) and crashes
before returning, so p cannot be NULL after the call. The guard was
dead code; the "preserve allocation on OOM" behavior advertised in
the original commit message never actually triggered.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: WonderMr

furi/core/memmgr.c

@@ -26,12 +26,10 @@ void* realloc(void* ptr, size_t size) {
 
     void* p = pvPortMalloc(size);
     if(ptr != NULL) {
-        if(p != NULL) {
-            size_t old_size = memmgr_heap_get_block_size(ptr);
-            size_t copy_size = old_size < size ? old_size : size;
-            memcpy(p, ptr, copy_size);
-            vPortFree(ptr);
-        }
+        size_t old_size = memmgr_heap_get_block_size(ptr);
+        size_t copy_size = old_size < size ? old_size : size;
+        memcpy(p, ptr, copy_size);
+        vPortFree(ptr);
     }
 
     return p;

furi/core/string.c

@@ -187,7 +187,7 @@ int furi_string_cat_vprintf(FuriString* v, const char format[], va_list args) {
 
     int size = vsnprintf(&ptr[old_size], alloc - old_size, format, args);
 
-    if(size > 0 && (old_size + (size_t)size + 1 >= alloc)) {
+    if(size > 0 && (old_size + (size_t)size + 1 > alloc)) {
         // Buffer too small — grow and retry
         ptr = m_str1ng_fit2size(v->string, old_size + (size_t)size + 1);
         size = vsnprintf(