feat(rules): add post-request rules system with response manipulation (#160)

* Add comprehensive post-request rules support for response phase
* Enable response body, status, and header manipulation via set commands
* Refactor command handlers to support both request and response phases
* Implement response modifier system for post-request template execution
* Support response-based rule matching with status and header checks
* Add comprehensive benchmarks for matcher performance
* Refactor authentication and proxying commands for unified error handling
* Support negated conditions with !
* Enhance error handling, error formatting and validation
* Routes: add `rule_file` field with rule preset support
* Environment variable substitution: now supports variables without `GODOXY_` prefix

* new conditions:
  * `on resp_header <key> [<value>]`
  * `on status <status>`
* new commands:
  * `require_auth`
  * `set resp_header <key> <template>`
  * `set resp_body <template>`
  * `set status <code>`
  * `log <level> <path> <template>`
  * `notify <level> <provider> <title_template> <body_template>`

internal/route/rules/parser_test.go

@@ -49,9 +49,9 @@ func TestParser(t *testing.T) {
 		},
 		{
 			name:    "regex_escaped",
-			input:   `foo regex(\b\B\s\S\w\W\d\D\$\.)`,
+			input:   `foo regex(\b\B\s\S\w\W\d\D\$\.\(\)\{\}\|\?\"\')`,
 			subject: "foo",
-			args:    []string{`regex(\b\B\s\S\w\W\d\D\$\.)`},
+			args:    []string{`regex(\b\B\s\S\w\W\d\D\$\.\(\)\{\}\|\?"')`},
 		},
 		{
 			name:    "quote inside argument",
@@ -71,6 +71,12 @@ func TestParser(t *testing.T) {
 			subject: "foo",
 			args:    []string{"glob(\"`/**/to/path`\")"},
 		},
+		{
+			name:    "complex_regex",
+			input:   `path !regex("^(_next/static|_next/image|favicon.ico).*$")`,
+			subject: "path",
+			args:    []string{`!regex("^(_next/static|_next/image|favicon.ico).*$")`},
+		},
 		{
 			name:    "chaos",
 			input:   `error 403 "Forbidden "foo" "bar""`,
@@ -170,6 +176,53 @@ func TestParser(t *testing.T) {
 			})
 		}
 	})
+
+	t.Run("negated", func(t *testing.T) {
+		test := `!error 403 "Forbidden"`
+		subject, args, err := parse(test)
+		expect.NoError(t, err)
+		expect.Equal(t, subject, "!error")
+		expect.Equal(t, args, []string{"403", "Forbidden"})
+	})
+}
+
+func TestFullParse(t *testing.T) {
+	input := `
+- name: login page
+  on: path /login
+  do: pass
+- name: require auth
+  on: path !regex("^(_next/static|_next/image|favicon.ico).*$")
+  do: require_auth
+- name: redirect to login
+  on: status 401 | status 403
+  do: proxy /login
+- name: proxy to backend
+  on: path glob("/api/v1/*")
+  do: proxy http://localhost:8999/
+- name: proxy to backend (old /auth)
+  on: path glob("/auth/*")
+  do: proxy http://localhost:8999/api/v1/`
+
+	var rules Rules
+	err := parseRules(input, &rules)
+	expect.NoError(t, err)
+	expect.Equal(t, len(rules), 5)
+	expect.Equal(t, rules[0].Name, "login page")
+	expect.Equal(t, rules[0].On.String(), "path /login")
+	expect.Equal(t, rules[0].Do.String(), "pass")
+	expect.Equal(t, rules[1].Name, "require auth")
+	expect.Equal(t, rules[1].On.String(), `path !regex("^(_next/static|_next/image|favicon.ico).*$")`)
+	expect.Equal(t, rules[1].Do.String(), "require_auth")
+	expect.Equal(t, rules[2].Name, "redirect to login")
+	expect.Equal(t, rules[2].On.String(), "status 401 | status 403")
+	expect.Equal(t, rules[2].Do.String(), "proxy /login")
+	expect.Equal(t, rules[3].Name, "proxy to backend")
+	expect.Equal(t, rules[3].On.String(), `path glob("/api/v1/*")`)
+	expect.Equal(t, rules[3].Do.String(), "proxy http://localhost:8999/")
+	expect.Equal(t, rules[4].Name, "proxy to backend (old /auth)")
+	expect.Equal(t, rules[4].On.String(), `path glob("/auth/*")`)
+	expect.Equal(t, rules[4].Do.String(), "proxy http://localhost:8999/api/v1/")
 }
 
 func BenchmarkParser(b *testing.B) {