fix(linux): avoid memory leak from unnecessary encoder re-probing (#5404)

src/platform/linux/misc.cpp

@@ -1247,7 +1247,15 @@ namespace platf {
    * @return Always `true` because Linux GPU changes are not tracked by this backend.
    */
   bool needs_encoder_reenumeration() {
-    // We don't track GPU state, so we will always reenumerate. Fortunately, it is fast on Linux.
+    // Only re-probe if the GPU render device changed (hotplug, driver reload).
+    // Full re-probing on every reconnect leaks ~20 MB due to FFmpeg CBS
+    // allocations during HEVC/AV1 codec validation.
+    static std::string last_render_device;
+    auto current = platf::resolve_render_device();
+    if (current == last_render_device) {
+      return false;
+    }
+    last_render_device = current;
     return true;
   }