docs(benchmarks): update benchmark report with Gin v1.12.0 results

[appleboy]

Summary

• Update benchmark data from Gin v1.6.3 (May 2020) to Gin v1.12.0 (March 2026)
• Update test environment from Travis CI / Ubuntu 16.04 / Go 1.14.2 to Apple M4 Pro / macOS / Go 1.25.8
• Improve report readability with table of contents, ranked summary tables, and organized sections

Key Results

Gin ranks #3 overall across all API benchmarks with zero memory allocations:

API Benchmark	#1	#2	#3 (Gin)
GitHub (203 routes)	Aero 6,646 ns	LARS 8,714 ns	Gin 9,058 ns
Google+ (13 routes)	Aero 323 ns	LARS 383 ns	Gin 412 ns
Parse (26 routes)	Aero 546 ns	LARS 669 ns	Gin 720 ns
Static (157 routes)	Denco 2,240 ns	Aero 2,872 ns	HttpTreeMux 4,031 ns (Gin #6: 5,566 ns)

Test plan

• Verified all benchmarks pass with go test -bench=. -benchmem
• Cross-referenced with go-http-routing-benchmark repo (already updated)

🤖 Generated with Claude Code

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