fix: update Codex compatibility and renderer performance

[szguicheng]

Summary

This PR focuses on two areas:

1. Update compatibility with the latest Codex UI

Codex has changed its main UI structure, native field names, and theme/runtime surface contracts. This PR updates Codex++ to recognize and work with the latest Codex UI, including:

• Modern main-surface, thread, header, message, composer, and scrolling structures.
• The current Codex theme variables and Dream Skin API mapping.
• Modern composer and thread lifecycle behavior.
• Correct native field matching and state mapping, so existing theme behavior follows the right Codex UI state.
• Safe cleanup and idempotent marker reconciliation when Codex changes or remounts UI sections.

2. Significantly improve Codex renderer performance

Previously, enabling the Codex++ renderer could make the entire Codex page feel noticeably sluggish. This PR substantially reduces renderer overhead by:

• Coalescing repeated DOM scans and deferred work.
• Avoiding redundant inline-style, attribute, text, and dataset writes.
• Reducing unnecessary layout reads and repeated alignment work.
• Throttling retry paths and preventing duplicate event-listener installation.
• Making conversation alignment incremental and stable instead of repeatedly resetting layout.
• Narrowing mutation observation to changes that can actually affect layout or behavior.

The result is a much lower renderer workload and a substantially smoother Codex UI when Codex++ is enabled.

No visual style is hard-coded into the application by this PR; theme appearance remains controlled by the theme layer.

Validation

• npm test: 121 passed
• cargo test -p codex-plus-core --test dream_skin_package --test dream_skin_runtime --test cdp_bridge: 131 passed, 1 ignored
• node --check assets/inject/renderer-inject.js
• npm run vite:build
• cargo build --release --target aarch64-apple-darwin
• Local validation against Codex 26.825.32147

Related historical context: #1755 and #1881.

[BigPizzaV3]

当前未看到 GitHub CI 结果（状态为 UNSTABLE）。该 PR 涉及 renderer/Dream Skin 的 14 个文件和约 973 行改动，请补跑并关联 CI，至少验证前端测试、核心 Rust 测试、Vite 构建和新版 Codex 实机兼容后再合并。

[szguicheng]

按要求已在最新提交 2eec08a 上完成补跑与兼容性验证。

本地验证

• npm test: 123 passed, 0 failed
• npm run check: passed
• npm run vite:build: passed
• cargo test --workspace: 1120 passed, 0 failed, 2 ignored
• cargo build --release --target aarch64-apple-darwin: passed
• node --check assets/inject/renderer-inject.js 和 git diff --check: passed

新版 Codex 实机验证

在 macOS 当前新版 Codex renderer（CDP，Codex 26.825.32147）中验证了右侧面板开关两种状态：

• Dream Skin runtime revision: 28-codex-plus-side-panel-layout
• 右侧面板关闭：thread viewport width 1662.5px，composer width 968px
• 右侧面板打开：thread viewport width 818.6px，composer width 786.6px
• 面板打开时 composer right 1060.1px，面板 left 1077.1px，无重叠
• footer 始终挂在新版 thread viewport（data-app-shell-main-content-layout="thread-edge-scroll"）内
• 右侧面板主题背景计算为 rgba(252, 252, 252, 0.72)，不再回退到默认白色

GitHub Actions

推送最新提交后，上游已生成新的 PR workflow run：

https://github.com/BigPizzaV3/CodexPlusPlus/actions/runs/33355484082

当前仍为 action_required，没有 job 结果。当前贡献者账号对上游仓库只有 read 权限，无法代替 Owner 批准 fork PR workflow；请点击 GitHub 的 “Approve and run workflows”，批准后该 run 才会执行并把 checks 结果关联到本 PR。

此前 workspace 测试暴露的 upstream_theme_assets hash 失败也已处理：四个 macOS Dream Skin vendor 资产是本 PR 有意修改的文件，已同步新的固定 hash；其余上游资产保护测试保持通过。

[BigPizzaV3]

请先在 GitHub Actions 中批准并运行当前 action_required 的 workflow。该 PR 涉及新版 renderer 和 Dream Skin 资产，待前端测试、Rust workspace、Vite 构建及 Windows/macOS 三平台 artifact checks 完成且全绿后再合并。

[BigPizzaV3]

改动覆盖新版 Dream Skin 兼容和 renderer 性能，方向与 #2082/#2064 的皮肤问题相关。当前 PR 没有可见的本仓三平台 CI 结果；请基于最新 main 重跑 Windows、macOS arm64/x64 artifact CI，并补充“开启皮肤后首页输入框可见、可创建新会话”的回归验证，之后再决定合并。

[BigPizzaV3]

感谢 PR。此分支（基于较旧 base、无 CI）与 #1712 是同一主题的对立实现——两边都改了 renderer-inject.js、dream_skin_runtime.rs、assets.rs 及对应测试，逐一合入会冲突（asset 字节基线 + runtime 逻辑重写）。\n\n#1712 保留是因为：base 更新、已 rebase（9/05）、含 Windows 适配且 fork 三平台 CI 通过，语义上就是主线在等的 Dream Skin→Codex 26.825 对齐。你的 #2050 里「renderer 性能优化」（合并 DOM 扫描/去抖、减少重复内联写、减负布局读取）是主线仍然想要的能力，但与 #2093 正在做的 renderer 性能工作目标重合。建议：拆出纯性能优化部分，基于合并了 #1712 的最新 main + 与 #2093 协调后重新提一个针对性的 PR；Dream Skin 本体对齐请走 #1712。\n\n本分支暂时关闭，可随时重开或参照上面方向另提新分支。