v12.2.0

• Added SinkFlushReason and Sink::flush_sink(SinkFlushReason) so custom sinks can opt in to distinguishing periodic backend flushes, explicit logger->flush_log() flushes, and final backend shutdown flushes.
• Fixed the built-in signal handler suppressing core dumps for fatal signals. (#962)
• Improve frontend codegen.
• Added missing includes to quill module. (#960)
• Fixed indexed placeholders and JSON messages in interval rate-limited logs.
• Added overflow protection for backend duration settings and timestamp grace periods.
• Repeated backend error notifications are now rate-limited.
• Fixed duplicate flushes when multiple threads share a logger configured with set_immediate_flush(N) where N > 1.
• Removed the QUILL_X86ARCH build option along with the x86 cache-line flush and prefetch code it enabled. Benchmarks on Intel and AMD systems across several thread-pinning topologies showed no measurable benefit.