docs(i18n): fully retranslate the zh Dynamic MIG pages for reservation-first Dynamic MIG

[saiyam1814]

Summary

#794 rewrites the English Dynamic MIG documentation for the reservation-first flow in v2.10 (docs/userguide/nvidia-device/dynamic-mig-support.md, docs/developers/dynamic-mig.md, and the example page). The matching zh pages under i18n/zh/docusaurus-plugin-content-docs/current/ only received short scoped notes pointing at the new behavior, so the v2.9 body text still describes the old flow in Chinese.

This issue tracks the full zh retranslation, as requested in the #794 review.

Scope

• i18n/zh/docusaurus-plugin-content-docs/current/userguide/nvidia-device/dynamic-mig-support.md
• i18n/zh/docusaurus-plugin-content-docs/current/developers/dynamic-mig.md
• i18n/zh/docusaurus-plugin-content-docs/current/userguide/nvidia-device/examples/dynamic-mig-example.md

Keep the annotation names, the metric rename with the legacyMetrics fallback, the upgrade ordering, and the MIG Manager boundary aligned with the English pages. Frozen versioned docs stay untouched.

Ordering

• Start after docs(mig): document reservation-first Dynamic MIG #794 merges so the translation works from the final English text.
• docs: standardize sidebar label and URL naming #806 renames the example page to assign-task-to-mig-instance.md; the zh file name follows whichever PR lands second.

[saiyam1814]

The full zh translation of all three pages moved into #794 itself (commit 0613afa) after review asked for locale parity in the same change. This issue can be closed once #794 merges.