perf(proxy): optimize hot request paths

- Cache route handlers, simplify NoRoute path normalization, and reduce matcher/header allocations

- Honor configured transport pool limits in auto mode and add hotpath regression benchmarks/tests

proxy/perf_compare_test.go

@@ -0,0 +1,88 @@
+package proxy
+
+import (
+	"net/http"
+	"testing"
+
+	"ghproxy/config"
+
+	"github.com/infinite-iroha/touka"
+)
+
+var benchmarkHeaderSource = http.Header{
+	"Accept":            {"text/plain"},
+	"Accept-Encoding":   {"gzip"},
+	"Connection":        {"keep-alive"},
+	"User-Agent":        {"curl/8.0.1"},
+	"X-Test":            {"one", "two"},
+	"CF-Connecting-IP":  {"127.0.0.1"},
+	"X-Forwarded-For":   {"127.0.0.1"},
+	"Transfer-Encoding": {"chunked"},
+}
+
+func BenchmarkMatcherGithubRelease(b *testing.B) {
+	cfg := &config.Config{
+		Auth: config.AuthConfig{Enabled: true, Method: "header", ForceAllowApi: false},
+	}
+
+	b.ReportAllocs()
+	for i := 0; i < b.N; i++ {
+		_, _, _, _ = Matcher("https://github.com/WJQSERVER-STUDIO/ghproxy/releases/download/v1.0.0/asset.tar.gz", cfg)
+	}
+}
+
+func BenchmarkMatcherRaw(b *testing.B) {
+	cfg := &config.Config{
+		Auth: config.AuthConfig{Enabled: true, Method: "header", ForceAllowApi: false},
+	}
+
+	b.ReportAllocs()
+	for i := 0; i < b.N; i++ {
+		_, _, _, _ = Matcher("https://raw.githubusercontent.com/WJQSERVER-STUDIO/ghproxy/main/README.md", cfg)
+	}
+}
+
+func BenchmarkMatcherGist(b *testing.B) {
+	cfg := &config.Config{
+		Auth: config.AuthConfig{Enabled: true, Method: "header", ForceAllowApi: false},
+	}
+
+	b.ReportAllocs()
+	for i := 0; i < b.N; i++ {
+		_, _, _, _ = Matcher("https://gist.githubusercontent.com/user/abcdef1234567890/raw/file.txt", cfg)
+	}
+}
+
+func BenchmarkMatcherAPI(b *testing.B) {
+	cfg := &config.Config{
+		Auth: config.AuthConfig{Enabled: true, Method: "header", ForceAllowApi: false},
+	}
+
+	b.ReportAllocs()
+	for i := 0; i < b.N; i++ {
+		_, _, _, _ = Matcher("https://api.github.com/repos/WJQSERVER-STUDIO/ghproxy/releases", cfg)
+	}
+}
+
+func BenchmarkSetRequestHeadersClone(b *testing.B) {
+	ctx := &touka.Context{Request: &http.Request{Header: benchmarkHeaderSource}}
+	cfg := &config.Config{}
+
+	b.ReportAllocs()
+	for i := 0; i < b.N; i++ {
+		req := &http.Request{Header: make(http.Header)}
+		setRequestHeaders(ctx, req, cfg, "clone")
+	}
+}
+
+func BenchmarkSetRequestHeadersRawCustom(b *testing.B) {
+	ctx := &touka.Context{Request: &http.Request{Header: benchmarkHeaderSource}}
+	cfg := &config.Config{}
+	cfg.Httpc.UseCustomRawHeaders = true
+
+	b.ReportAllocs()
+	for i := 0; i < b.N; i++ {
+		req := &http.Request{Header: make(http.Header)}
+		setRequestHeaders(ctx, req, cfg, "raw")
+	}
+}