fix(nginx): fix broken redirects and multi-hop chains (#2313)

- Fix 27 redirect destinations pointing to 404 pages (monitoring
sub-pages, proxy examples, get-most-of-actors sub-pages, testing-
and-maintenance, analyze-pages-and-fix-errors, scrape-with-sitemaps)
- Remove 2 unreachable duplicate rewrite rules (same source pattern
appearing twice with different destinations — first match always won)
- Collapse ~80 multi-hop redirect chains into single hops: access-
rights → collaboration, actors sub-pages, tutorials, development section
restructure, data-collection → scraping-basics-javascript

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Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: TC-MO