refactor(executor): split providers and preserve legacy entrypoints

feat: passthrough upstream response headers to clients

feat(executor): add session ID and HMAC-SHA256 signature generation for iFlow API requests

refactor(translator, executor): remove redundant `bytes.Clone` calls for improved performance

refactor(executor): optimize payload cloning and streamline SDK translator usage

feat(openai): add responses/compact support

feat(executor): add request_id to error logs

feat(executor): apply payload rules using requested model

feat(registry): support provider-specific model info lookup

refactor(thinking): pass source and target formats to ApplyThinking for cross-format validation

fix(executor): properly handle thinking application errors

refactor: improve thinking logic

feat(executor): add HttpRequest support across executors for better http request handling

feat(executor): enhance payload translation with original request context

fix(iflow): remove thinking field from request body in thinking config handler

refactor(iflow): simplify thinking config handling for GLM and MiniMax models

refactor(executor): resolve upstream model at conductor level before execution

fix(executor): use upstream model for thinking config and payload translation

feat(iflow): add model-specific thinking configs for GLM-4.7 and MiniMax-M2.1

feat(iflow): add thinking support for iFlow models

refactor(thinking): export thinking helpers

fix(executor): add `allowCompat` support for reasoning effort normalization

fix(codex): raise default reasoning effort to medium

Merge pull request #481 from sususu98/fix/increase-buffer-size

fix(runtime): validate thinking config in iflow and qwen

fix(runtime): unify reasoning effort metadata overrides

feat(util): implement dynamic thinking suffix normalization and refactor budget resolution logic

fix(executor): increase buffer size for stream scanners to 50MB across multiple executors

**feat(auth): add AuthIndex for diagnostics and ensure usage recording**

feat(auth): add iFlow cookie-based authentication support

**fix(runtime): simplify scanner buffer allocation in executor implementations**

**feat(runtime): add payload configuration support for executors**

refactor(executor): summarize API error bodies of html in debug logs

Fixed: #140 #133 #80

Refactor executor error handling and usage reporting

feat(iflow): add masked token logs; increase refresh lead to 24h

Enhance logging for API requests and responses across executors

feat(registry/runtime): add Gemini 2.5 model and increase buffer sizes

feat(iflow): Add User-Agent header to API requests

feat: Add support for iFlow provider