Add zh-CN localization for embedded dashboard

[vimalinx]

Summary

• add a lightweight runtime i18n layer (zh-CN + en) for the embedded dashboard UI
• localize common shell text, toasts, confirm dialogs, status/error strings, and markdown copy button labels
• add a locale toggle in the header and wire locale-aware date/number formatting in scheduler and hands pages
• include related lint-safe JS refactors and a small clippy cleanup in CLI diagnostics path

Verification

• cargo build --workspace --lib
• cargo test --workspace
• cargo clippy --workspace --all-targets -- -D warnings

[Jengro777]

@vimalinx
Is there any new progress?

[jaberjaber23]

Reviewed and approved. Has merge conflicts with recent changes. Please rebase onto current main and we will merge.

[Jengro777]

@vimalinx
Looking forward to

[vimalinx]

Updated this PR onto the latest main and resolved the merge conflicts.

I also reran cargo test locally on the merged result and it passed.

[Jengro777]

Updated this PR onto the latest main and resolved the merge conflicts.

I also reran cargo test locally on the merged result and it passed.

Great, looking forward to the merger.

[Vimalinx-zero]

Rebased onto the latest main and resolved the previous conflicts.

I reran cargo test locally on the updated branch, and GitHub is currently showing this PR as mergeable on my side. Ready for maintainer merge whenever convenient.

[Jengro777]

@jaberjaber23
Can it be merged?

[Jengro777]

Quick feedback from the community:
https://github.com/librefang/librefang

[vimalinx]

Rebased this branch onto the current main and resolved the merge conflicts. GitHub is now showing the PR as mergeable on my side.

Verification note: a full cargo test run is currently blocked by an existing compile error in crates/openfang-runtime/src/mcp.rs (StreamableHttpClientTransportConfig non-exhaustive struct construction), which is also present on the current main. The actual diff on this branch remains limited to the dashboard zh-CN localization files and related merge-resolution updates.

[Jengro777]

@vimalinx

This project is too disrespectful to the community. It is recommended to move to:https://github.com/librefang/librefang