chore(docs): drop references to things the stack removed - #2448

🟢 Confidence 10/10 · safe to merge. Comment and doc-string cleanup plus one dead Env field; a full-tree grep confirms nothing reads MAPLE_DB_URL at the head.
_{no findings · tests not needed · risk low}

Removes the reader-less MAPLE_DB_URL from Env and .env.example and corrects stale comments (scraper Dockerfile, nginx.conf, routeTree.gen.ts, Llm.ts path). Every claim holds against the head tree; safe to merge.

Before merge

• Infra · Check every environment has what this config now expects · apps/scraper/Dockerfile

_{2b4c920 · Reply "won't fix" to dismiss a finding, or mention @maple-review-bot to ask about one.}