[cvik]

Summary

Migrate latest main (871c8a2, including #95–#98) to Zig 0.17.0. Preserve main's public APIs, cooperative io_uring task work, registered socket, shared provided-buffer ring, bounded CON storage, and remote benchmark support. Retain main's coapz v0.4.0 dependency.

• Replace array multiplication with typed splats and adopt backing-integer builtins.
• Update build argument forwarding, optimization names, minimum compiler version, CI and docs.
• Preserve native-endian socket memory across changed @bitCast semantics and handle the updated Linux waitpid status type.
• Repair CCM array/vector bit-cast scalarization using unaligned byte-vector views, with independent ciphertext/authentication tests.
• Port new remote benchmark credential-path formatting and accept both compiler optimization names in the comparison harness.

Verification

217 tests pass in debug, safe, fast and software-AES/baseline-CPU configurations. Normal/optimized builds, docs, ARM64 cross-builds, the full 24-scenario optimized benchmark suite, and remote benchmark integration checks pass. Integration covers IPv4/IPv6, plain/DTLS, single/multi clients, receipt accounting, leases/capacity and MID-wrap/duplicate handling. Cross-target binaries were not executed.

Performance

docs/ZIG_017_PERFORMANCE.md preserves the original migration's five-run alternating comparisons and explicitly marks them historical: they predate this rebase and do not establish parity against latest main. The original 23% large-payload DTLS NON slowdown was repaired by the CCM vector-view change, which is retained.

The rebased full suite reports zero request errors; an isolated 1000-byte single-thread DTLS NON verification run measures 417,149 req/s with zero errors. These are not matched latest-main comparisons. Keep draft pending performance review or explicit acceptance of the remaining limitations; no blanket regression-free claim is made.