docs: center scraping guidance on auto

[gildesmarais]

What changed

• Make auto the recommended strategy across custom-feed, dynamic-content, CLI, MCP, and troubleshooting docs.
• Document default as a fixed direct-request override without exposing HTTP adapter implementation details.
• Keep explicit Botasaurus selection for browser-specific controls and targeted diagnosis.
• Describe web workers and timeout contracts behaviorally, and keep reverse-proxy HTTPS as the supported deployment path.
• Correct capture strategy persistence, MCP strategy discovery, and the UnknownStrategy troubleshooting entry against runtime behavior.

Why

End users should choose between the normal auto path and deliberate fixed-mode overrides. HTTP client and web server choices are implementation details; documenting them throughout the user journey made adapter replacements look like user-facing migrations and weakened the strategy interface.

Risk

• Low — documentation-only changes.
• The core runtime still publishes compatibility aliases through strategy discovery; the docs describe canonical choices without promoting those aliases.
• html2rss-web/docker-compose.yml still sets the old timeout variable. These docs describe aligned runtime defaults and tell operators to set REQUEST_TIMEOUT_SECONDS explicitly rather than claiming Compose configures it.

Review map

Review map: whole PR is small — start at src/content/docs/ruby-gem/reference/strategy.mdx, then check src/content/docs/ruby-gem/guides/handling-dynamic-content.mdx and src/content/docs/web-application/reference/env-variables.mdx.

Validation

• make lint
• make test — 7 files, 25 tests passed
• make build — 44 pages built and 58 HTML files indexed
• Fresh documentation findings review — readiness Yes