docs: translate remaining Chinese content to English in doris-debug skills

[ixzc]

Summary

Follow-up to #3 — translates all remaining Chinese text in the doris-debug skill files to English, so the skills are fully usable for English-speaking users and tooling.

What changed

18 files under skills/doris-debug/ (+858 / -856):

Area	Files
Shared references	03-cir-case-index.md, 04-metrics-guide.md, 05-config-quick-ref.md, 01-common-commands.md, 02-source-map.md
Shared guides	cascade-import-wal-versions.md, cascade-query-timeout-exchange.md
Case files	node ×3, query ×2, import ×2, compaction ×1, cloud ×1, data-lake ×1, resource-isolation ×1

Translation rules applied

• All Chinese prose, headings, table cells, and list items → natural technical English
• Author-written annotations inside code blocks (bash # comments, SQL -- comments, profile/log annotations, flow diagrams) → translated
• Command lines, SQL statements, config keys, metric names, class/method names, log output → left untouched
• Markdown structure (frontmatter, headings, tables, code fences) preserved exactly

Verification

grep -rcP '[\x{4e00}-\x{9fff}]' skills/ returns zero matches — no Chinese text remains in the skills directory.