Squashed 'external/toxcore/c-toxcore/' changes from c9cdae001..9ed2fa80d

9ed2fa80d fix(toxav): remove extra copy of video frame on encode
de30cf3ad docs: Add new file kinds, that should be useful to all clients.
d5b5e879d fix(DHT): Correct node skipping logic timed out nodes.
30e71fe97 refactor: Generate event dispatch functions and add tox_events_dispatch.
8fdbb0b50 style: Format parameter lists in event handlers.
d00dee12b refactor: Add warning logs when losing chat invites.
b144e8db1 feat: Add a way to look up a file number by ID.
849281ea0 feat: Add a way to fetch groups by chat ID.
a2c177396 refactor: Harden event system and improve type safety.
8f5caa656 refactor: Add MessagePack string support to bin_pack.
34e8d5ad5 chore: Add GitHub CodeQL workflow and local Docker runner.
f7b068010 refactor: Add nullability annotations to event headers.
788abe651 refactor(toxav): Use system allocator for mutexes.
2e4b423eb refactor: Use specific typedefs for public API arrays.
2baf34775 docs(toxav): update idle iteration interval see 679444751876fa3882a717772918ebdc8f083354
2f87ac67b feat: Add Event Loop abstraction (Ev).
f8dfc38d8 test: Fix data race in ToxScenario virtual_clock.
38313921e test(TCP): Add regression test for TCP priority queue integrity.
f94a50d9a refactor(toxav): Replace mutable_mutex with dynamically allocated mutex.
ad054511e refactor: Internalize DHT structs and add debug helpers.
8b467cc96 fix: Prevent potential integer overflow in group chat handshake.
4962bdbb8 test: Improve TCP simulation and add tests
5f0227093 refactor: Allow nullable data in group chat handlers.
e97b18ea9 chore: Improve Windows Docker support.
b14943bbd refactor: Move Logger out of Messenger into Tox.
dd3136250 cleanup: Apply nullability qualifiers to C++ codebase.
1849f70fc refactor: Extract low-level networking code to net and os_network.
8fec75421 refactor: Delete tox_random, align on rng and os_random.
a03ae8051 refactor: Delete tox_memory, align on mem and os_memory.
4c88fed2c refactor: Use `std::` prefixes more consistently in C++ code.
72452f2ae test: Add some more tests for onion and shared key cache.
d5a51b09a cleanup: Use tox_attributes.h in tox_private.h and install it.
b6f5b9fc5 test: Add some benchmarks for various high level things.
8a8d02785 test(support): Introduce threaded Tox runner and simulation barrier
d68d1d095 perf(toxav): optimize audio and video intermediate buffers by keeping them around
REVERT: c9cdae001 fix(toxav): remove extra copy of video frame on encode

git-subtree-dir: external/toxcore/c-toxcore
git-subtree-split: 9ed2fa80d582c714d6bdde6a7648220a92cddff8

testing/support/public/mpsc_queue.hh

@@ -0,0 +1,83 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later
+ * Copyright © 2026 The TokTok team.
+ */
+#ifndef C_TOXCORE_TESTING_SUPPORT_MPSC_QUEUE_H
+#define C_TOXCORE_TESTING_SUPPORT_MPSC_QUEUE_H
+
+#include <condition_variable>
+#include <deque>
+#include <mutex>
+
+namespace tox::test {
+
+/**
+ * @brief Multiple Producer, Single Consumer Queue.
+ *
+ * This queue implementation provides thread-safe access for multiple producers
+ * pushing items and a single consumer popping items. It uses a `std::mutex`
+ * and `std::condition_variable` for synchronization.
+ *
+ * @tparam T The type of elements stored in the queue.
+ */
+template <typename T>
+class MpscQueue {
+public:
+    MpscQueue() = default;
+    ~MpscQueue() = default;
+
+    // Disable copy/move to prevent accidental sharing/slicing issues
+    MpscQueue(const MpscQueue &) = delete;
+    MpscQueue &operator=(const MpscQueue &) = delete;
+
+    /**
+     * @brief Pushes a value onto the queue.
+     * Thread-safe (Multiple Producers).
+     */
+    void push(T value)
+    {
+        {
+            std::lock_guard<std::mutex> lock(mutex_);
+            queue_.push_back(std::move(value));
+        }
+        cv_.notify_one();
+    }
+
+    /**
+     * @brief Pops a value from the queue, blocking if empty.
+     * Thread-safe (Single Consumer).
+     */
+    T pop()
+    {
+        std::unique_lock<std::mutex> lock(mutex_);
+        cv_.wait(lock, [this] { return !queue_.empty(); });
+        T value = std::move(queue_.front());
+        queue_.pop_front();
+        return value;
+    }
+
+    /**
+     * @brief Tries to pop a value from the queue without blocking.
+     * Thread-safe (Single Consumer).
+     *
+     * @param out Reference to store the popped value.
+     * @return true if a value was popped, false if the queue was empty.
+     */
+    bool try_pop(T &out)
+    {
+        std::lock_guard<std::mutex> lock(mutex_);
+        if (queue_.empty())
+            return false;
+        out = std::move(queue_.front());
+        queue_.pop_front();
+        return true;
+    }
+
+private:
+    std::deque<T> queue_;
+    std::mutex mutex_;
+    std::condition_variable cv_;
+};
+
+}  // namespace tox::test
+
+#endif  // C_TOXCORE_TESTING_SUPPORT_MPSC_QUEUE_H