Improve Chapter 01 documentation lesson

[jules-tth]

Summary

• Rewrite the Chapter 01 man pages and online documentation lesson around practical Linux operations
• Cover manual sections, search workflows, syntax markers, package docs, and trustworthy online sources
• Add a local-docs-first lab and review questions

Verification

• python3 -m mkdocs build --strict
• git diff --check
• find docs -type f -name "*.md" -size 0 -print
• make build

Duplicate prevention

• Checked open PRs for 1.07_man_pages_and_other_on-line_documentation before implementation and immediately before PR creation; none were open for this file.