feat(rules): introduce block DSL, phase-based execution (#203)

* chore(deps): update submodule goutils

* docs(http): remove default client from README.md

* refactor(rules): introduce block DSL, phase-based execution, and flow validation

- add block syntax parser/scanner with nested @blocks and elif/else support
- restructure rule execution into explicit pre/post phases with phase flags
- classify commands by phase and termination behavior
- enforce flow semantics (default rule handling, dead-rule detection)
- expand HTTP flow coverage with block + YAML parity tests and benches
- refresh rules README/spec and update playground/docs integration
- Default rules act as fallback handlers that execute only when no matching non-default rule exists in the pre phase
- IfElseBlockCommand now returns early when a condition matches with a nil Do block, instead of falling through to else blocks
- Add nil check for auth handler to allow requests when no auth is configured

* fix(rules): buffer log output before writing to stdout/stderr

* refactor(api/rules): remove IsResponseRule field from ParsedRule and related logic

* docs(rules): update examples to use block syntax

internal/route/rules/on_test.go

@@ -12,6 +12,7 @@ import (
 	"github.com/yusing/godoxy/internal/route"
 	"github.com/yusing/godoxy/internal/route/routes"
 	. "github.com/yusing/godoxy/internal/route/rules"
+	httputils "github.com/yusing/goutils/http"
 	expect "github.com/yusing/goutils/testing"
 	"golang.org/x/crypto/bcrypt"
 )
@@ -386,7 +387,7 @@ func TestOnCorrectness(t *testing.T) {
 
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			w := httptest.NewRecorder()
+			w := httputils.NewResponseModifier(httptest.NewRecorder())
 			var on RuleOn
 			err := on.Parse(tt.checker)
 			expect.NoError(t, err)