refactor: adopt Go 1.26+ standard library modernizations

- Use maps.Copy in hooks dispatcher instead of manual map loop
- Remove implicit loop variable capture in router_abort_test (Go 1.26 semantics)
- Use range without index in http_test where index unused
- Use min() builtin in script_test instead of manual min computation

internal/agent/router_abort_test.go

@@ -138,7 +138,6 @@ func TestAbortRun_AlreadyAborting(t *testing.T) {
 	var wg sync.WaitGroup
 	wg.Add(n)
 	for i := range n {
-		i := i
 		go func() {
 			defer wg.Done()
 			results[i] = r.AbortRun(runID, sessionKey)

internal/hooks/dispatcher.go

@@ -5,6 +5,7 @@ import (
 	"errors"
 	"fmt"
 	"log/slog"
+	"maps"
 	"sync"
 	"sync/atomic"
 	"time"
@@ -276,9 +277,7 @@ func (d *stdDispatcher) runSync(ctx context.Context, ev Event, chain []HookConfi
 // blocks or the chain aborts.
 func cloneMap(m map[string]any) map[string]any {
 	out := make(map[string]any, len(m))
-	for k, v := range m {
-		out[k] = v
-	}
+	maps.Copy(out, m)
 	return out
 }
 
@@ -303,9 +302,7 @@ func applyBuiltinMutation(ev *Event, updated map[string]any, allowlist []string)
 			if ev.ToolInput == nil {
 				ev.ToolInput = map[string]any{}
 			}
-			for k, v := range m {
-				ev.ToolInput[k] = v
-			}
+			maps.Copy(ev.ToolInput, m)
 		} else {
 			for k, v := range m {
 				if _, ok := allowSet["toolInput."+k]; ok {

internal/hooks/handlers/http_test.go

@@ -236,7 +236,7 @@ func TestHTTP_ResponseBodyCappedAt1MiB(t *testing.T) {
 		for i := range chunk {
 			chunk[i] = 'x'
 		}
-		for i := 0; i < 32; i++ { // 32 × 64 KiB = 2 MiB
+		for range 32 { // 32 × 64 KiB = 2 MiB
 			w.Write(chunk)
 		}
 	}))

internal/hooks/handlers/script_test.go

@@ -214,10 +214,7 @@ func TestStdoutCapTruncates(t *testing.T) {
 		t.Fatalf("stdout exceeded cap: %d bytes", len(res.Stdout))
 	}
 	if !strings.Contains(res.Stdout, "truncated") {
-		end := 200
-		if end > len(res.Stdout) {
-			end = len(res.Stdout)
-		}
+		end := min(200, len(res.Stdout))
 		t.Fatalf("truncation marker missing: %q", res.Stdout[:end])
 	}
 }