Add ToC and compact reference creation for AI Assistant, improve raw-markdown conversions

[emrberk]

• Adds orphaned railroad definitions (for some diagrams, svgs were present, but definitions were not)
• Removes unused railroad definitions
• Adds conversions for all railroad diagrams into compact definitions and markdown pages
• Extends component conversions with RemoteRepoExample and ILPClientsTable
• Adds table of contents creation to prebuild phase, for web console ai assistant tools to consume:
  → https://preview-258--questdb-documentation.netlify.app/docs/web-console/toc-list.json
  → https://preview-258--questdb-documentation.netlify.app/docs/web-console/functions-docs.json
  → https://preview-258--questdb-documentation.netlify.app/docs/web-console/operators-docs.json
  → https://preview-258--questdb-documentation.netlify.app/docs/web-console/sql-docs.json
• Adds compact reference creation to prebuild phase, for web console ai assistant to embed into vector store:
  → https://preview-258--questdb-documentation.netlify.app/docs/reference-full.md)
• Adds a new GH Action for reminding component converters when a component is modified

[github-actions]

🚀 Build success!

Latest successful preview: https://preview-258--questdb-documentation.netlify.app/docs/

Commit SHA: 5734606

📦 Build generates a preview & updates link on each commit.

[github-actions]

🤖 Component Converter Reminder

A component in src/components/ or src/theme/ was modified in this pull request.

We are creating markdown correspondents of every path (e.g. questdb.com/docs/quick-start → questdb.com/docs/quick-start/index.md) for LLM consumption.
If the component usage is shadowing useful content, it may need a converter for markdown output in convert-components.js.

Quick Check

• ✅ Content component (code, tables, data) → Add converter if not exists
• ❌ UI/visual component (styling, buttons, decorative) → No converter needed

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💡 This is a friendly reminder, not a blocker. Ignore if not applicable.