v1.5.1 — 6.1x large-payload speedup + fresh benchmarks

🔒 Covered by ReqProof — L3 Assurance (123 requirements, 0 errors, 0 warnings)

Performance — 6.1x large-payload speedup

Two optimizations found via ADHD-driven profiling + 10 parallel worktree experiments:

1. Fix stringEnd unbounded backslash scan — stringEndConfig was scanning the ENTIRE remaining parent document for backslashes instead of just the string body. Bounded to data[:firstQuote]. 128µs → 22µs (5.8x).

2. SWAR string scan — replaced two separate bytes.IndexByte calls with a single inline 8-byte SWAR loop checking for both " and \ simultaneously. 22µs → 21µs (additional 8%).

Fresh benchmarks (all libraries at latest versions)

Methodology: Apple M4 Max (ARM64), Go 1.26.3, median of 5 runs. All comparison libraries updated. The encoding/json benchmark no longer uses ffjson-generated methods (fixed #126 in v1.3.1).

Payload	jsonparser	encoding/json	easyjson	jsonparser advantage
Small (190B)	382 ns / 0 allocs	1,335 ns / 9 allocs	312 ns / 4 allocs	3.5x faster, 0 allocs
Medium (2.4kB)	3,894 ns / 0 allocs	10,564 ns / 18 allocs	2,444 ns / 7 allocs	2.7x faster, 0 allocs
Large (24kB)	20,788 ns / 0 allocs	134,123 ns / 147 allocs	32,765 ns / 134 allocs	6.4x faster, 0 allocs

jsonparser is the fastest library overall on large payloads and the only zero-allocation parser.

Full changelog: CHANGELOG.md