Merges Jim Calabro's comprehensive correctness improvements: - non-minimal CBOR encoding rejection (RFC 8949) - UTF-8 validation on text strings - map key sort order + duplicate key rejection - safe integer arithmetic throughout (std.math.add/cast) - errdefer on all decode allocations - low-level zero-copy CBOR read/write API - MST tests ported from atmos, delete rebalancing fix - CAR v1 validation gaps, readUvarint overflow fix - ECDSA signature verification overflow fix - firehose smoke test against live production data - CBOR codec benchmarks decode+verify throughput: 290k → 202k fps (still 13x faster than Go). the regression is from correctness checks that were missing before. also: bump zig to 0.16.0-dev.3070, update CI, fix tangled.org URLs. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>