[WenG8868]

Summary

This PR adds full English/Chinese localization to ComfyUI MiniMax H3 Prompt Writer and introduces an embedded llama.cpp chat workspace, along with the supporting external-server backend, runtime diagnostics, and tests.

Changes

Localization

• Added web/i18n.js and web/locales/{en,zh-CN}.js, covering the Writer shell, workspaces, settings, model/runtime/provider panels, media tools, sequence, drafts, notifications, errors, and status messages.
• Added a language selector in settings; the preference is persisted only after an explicit user switch.
• The English interface remains unchanged; key parity between locales is enforced by tests.
• Toasts and status messages use replayable descriptors, so they refresh on language change without network requests or input side effects.

llama.cpp chat

• The Chat tab appears only when an external llama.cpp server is configured and a model is active; the iframe and host window sync language and theme via postMessage.
• Streaming SSE chat with thinking toggle, keep-loaded/unload model, stop generation, speed stats, and window protection while generating.
• Image/video attachments with count, size, and duration validation plus compression.
• Chat history is stored locally in the browser: text only, media tracked as counts, open and two-step delete, up to 30 conversations.
• Assistant replies render as Markdown (headings, lists, code blocks, tables, quotes, inline formatting; links restricted to http/https, no innerHTML); the copy button always copies the raw Markdown/input text.

Backend and stability

• Added external llama.cpp chat forwarding and cancellation endpoints without affecting the existing ComfyUI generation flow.
• Added backend/runtime_probe.py to probe native backend capabilities in a child process, avoiding pollution of the main process.
• Improved VRAM/runtime diagnostics, memory handling, and unmeasured-VRAM warnings.
• Fixed generate/refine being aborted by the 60-second fetch timeout; added a stable network error code for response-body read failures.

Testing

• Frontend: node --test tests/*.mjs — 368 tests passing; new cases for i18n, chat history, and Markdown rendering.
• Backend: 425 tests covering the external-server backend, route stability, memory, and runtime diagnostics.
• No new runtime dependencies.

Notes

• Chat history is stored only in browser localStorage and excludes image/video data.
• No breaking interface changes.