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/api/v1/docs/swagger.json

@@ -5093,11 +5093,6 @@
           "x-nullable": false,
           "x-omitempty": false
         },
-        "isResponseRule": {
-          "type": "boolean",
-          "x-nullable": false,
-          "x-omitempty": false
-        },
         "name": {
           "type": "string",
           "x-nullable": false,

internal/api/v1/docs/swagger.yaml

@@ -891,8 +891,6 @@ definitions:
     properties:
       do:
         type: string
-      isResponseRule:
-        type: boolean
       name:
         type: string
       "on":
@@ -1837,12 +1835,12 @@ definitions:
         type: string
       kernel_version:
         type: string
-      load_avg_5m:
-        type: string
       load_avg_15m:
         type: string
       load_avg_1m:
         type: string
+      load_avg_5m:
+        type: string
       mem_pct:
         type: string
       mem_total: