[lfu45757-star]

Summary

Add an optional, Windows-friendly Python bridge for chatting with a locally
authenticated Codex CLI, including single-image understanding and follow-up
questions about the most recent image.

Relationship to #110

Related to #110, but independent and complementary rather than a replacement:

	#110	This PR
Entry point	Node.js bridge + installable skill; macOS/Linux	Python SDK example + Windows launcher
Input	Text tasks	Text and one static image
Context	Resume an explicit Codex session	Bounded in-memory text history + latest image
Execution	Workspace-writing task agent	Chat-only, read-only sandbox, tools disabled
Image lifecycle	Not implemented	Validation, bounded download, 30-minute expiry, per-call temporary-file cleanup

This PR does not modify the skill/Node.js files proposed in #110 or change the
existing default echo example. It is based on the current upstream main, not
the older source archive used for local deployment.

Changes

• Add python/examples/codex_bot.py, codex_images.py and start-codex.cmd.
• Restrict handling to the QR-login account, filter stale/duplicate messages and
  preserve ordinary text conversation with bounded history.
• Attach normalized images using codex exec --image; support mixed image/text
  messages and separate follow-up messages. New images replace old ones.
• /reset clears both text and image context; image expiry and normal exit also
  release cached image data. No arbitrary files, multi-image comparisons, voice,
  video or remote computer-operation tools are enabled.
• Validate supported static formats, 10 MiB / 25 MP limits, EXIF orientation and
  metadata removal, and resize to a 2048-pixel maximum edge. Original decrypted
  images stay off disk; normalized temporary JPEGs are removed after each call,
  including error, timeout and cancellation paths.
• Add backward-compatible download_raw(..., max_bytes=None) to the Python SDK.
  When set, limit both the encrypted stream (with AES padding allowance) and
  decrypted bytes, including when Content-Length is absent.
• Add an optional Pillow extra, public setup/privacy/troubleshooting documentation,
  regression tests and Python CI dependency/CLI-help coverage.
• Ignore .venv/ and .codex-wechat/. No credentials, real user messages/images,
  machine-specific deployment paths, installed environments or runtime records
  are included.

Validation

• Windows / Python 3.12 offline regression suite against this upstream-based
  integration: 73 tests passed, plus 15 parameter subtests.
• python examples/codex_bot.py --help: passed without logging into WeChat.
• git diff --check: passed.
• The original local implementation was also live-tested with the Windows
  desktop-bundled Codex CLI 0.162.0-alpha.17.2: text returned CODEX_OK, and image
  input correctly read a synthetic image containing six random digits not present
  in the text prompt. Those CLI invocations did not connect to WeChat or send
  WeChat test messages.
• The CI changes exercise offline Python tests and help output on Windows,
  macOS and Linux. These new remote CI runs have not been claimed as passing yet.

Limitations

• This example needs a compatible native Codex executable and an image-capable
  model. Required CLI flags and the locally tested version are documented; it
  does not add another API key or make model calls in CI.
• It defaults to Chinese replies/help. Setup documentation includes English and a
  Chinese quick reference.
• Only the latest image is retained, for 30 minutes; follow-ups do not extend the
  expiry. Separate messages receive separate replies, not delayed batching.
• The SDK handles messages sequentially. Reset/help during an active model call
  is processed after the call finishes or times out (default 180 seconds).
• A forced process kill/power loss may leave temporary files. Local reset does not
  delete content already submitted to Codex/OpenAI.
• Live image transport through WeChat still requires user acceptance testing;
  no running local WeChat service was interrupted for this contribution.

中文摘要

补充 #110 尚未覆盖的 Windows/Python 图文聊天用法：单图识别、最近图片追问、
/reset 同时清空文字与图片，以及图片下载限额、格式校验和临时文件清理。
这是关闭电脑操作工具的聊天示例，不替代 #110 的任务执行和会话续接方案。