TKE-45: add TKE node maintenance doc

[wenjiehs]

What changed

• Added src/content/docs/basics/node/03-maintain-node.md for TKE node maintenance.
• Added the new page to the node management table in src/content/docs/basics/index.md.

Why

TKE-45 reported that the validation target src/content/docs/basics/node/03-maintain-node.md was missing, preventing single-page Static/Dry Run Compile for the node maintenance guide.

Doc Change Report

• Source issue: TKE-45
• canonical_doc_path: src/content/docs/basics/node/03-maintain-node.md
• operation_id: tke.node.maintain
• Modified scope:
  • src/content/docs/basics/node/03-maintain-node.md
  • src/content/docs/basics/index.md
• Fact sources:
  • Tencent Cloud 驱逐或封锁节点: https://cloud.tencent.com/document/product/457/32205, page updated 2026-06-03 16:36:04; used for cordon/uncordon/drain behavior and console operation semantics.
  • Tencent Cloud TKE 集群中节点移出再移入操作指引: https://cloud.tencent.com/document/product/457/40771, page updated 2025-09-23 11:10:01; used for move-out/re-add flow, drain prechecks, PDB/local-storage risks, and data disk caution.
  • Tencent Cloud 应用高可用部署: https://cloud.tencent.com/document/product/457/40212, page updated 2026-03-16 14:43:52; used for PDB and availability risks during node eviction.
  • Tencent Cloud 节点概述: https://cloud.tencent.com/document/product/457/32201, page updated 2026-05-13 18:33:52; used to confirm node operation scope and node-related operation entry.
  • Existing repository docs: src/content/docs/basics/node/01-add-node.md, src/content/docs/basics/node/02-delete-node.md, src/content/docs/basics/node/04-describe-nodes.md, src/content/docs/basics/index.md; used for local style, related links, and section placement.
• Static Compile:
  • git diff --check passed.
  • Markdown code blocks use explicit languages (bash, text) where applicable.
  • No new cookbook was added; existing cookbook Python files compiled successfully.
  • MkDocs strict build skipped because this Astro/Starlight repo has no mkdocs.yml or mkdocs.yaml.
• Dry Run Compile:
  • python3 -m py_compile cookbook/cluster/create_cluster.py cookbook/cluster/delete_cluster.py cookbook/cluster/describe_clusters.py cookbook/common/auth.py cookbook/common/logger.py cookbook/supernode/deploy_gpu_pod.py cookbook/workload/deploy_nginx.py passed.
  • node --test test/navigation.test.mjs test/cookbooks.test.mjs test/create-cluster-autoupgrade.test.mjs passed.
  • npm run build passed after installing declared npm dependencies locally.
• Live Verify:
  • Not required. This change documents maintenance commands and console workflow only; no cookbook was added and no real Tencent Cloud/TKE resources were created, modified, or deleted.
• Remaining human confirmation:
  • None for documented facts. Production execution strategy remains reader/operator-specific and is not prescribed beyond official cautions.