docs: dedup lead paragraph, number on-this-page TOC

[pratyush618]

Two small docs-site fixes.

Duplicate lead paragraph

The frontmatter description already renders as the page lead (below the H1). 16 pages then repeated that same sentence — verbatim or lightly reworded — as their first body paragraph, so it showed twice (e.g. Quickstart's "Build your first task queue in 5 minutes."). Removed the redundant body paragraph on those pages. Left intro paragraphs that genuinely elaborate (e.g. prefork, node events) untouched.

Numbered on-this-page TOC

Top-level "On this page" entries are now auto-numbered (1., 2., …) via a CSS counter; sub-headings keep their dot marker. Any author-written N. prefix in a heading is stripped from the TOC label so the number isn't shown twice.

Verification

• pnpm build clean; pnpm run typecheck + biome check clean.
• Detected the duplicate pages by comparing each file's frontmatter description against its first body paragraph (exact + near-match).

Summary by CodeRabbit

• New Features

  • Added automatic numbering for top-level documentation table-of-contents entries.
  • Prevented duplicate numeric prefixes in H2 table-of-contents labels.
  • Added an informational overview callout to the Python Queue API reference.

• Documentation

  • Improved the job lifecycle page with an interactive state machine component.
  • Refined page descriptions and removed redundant introductory text across Java, Node.js, and Python documentation.
  • Clarified guide and API reference navigation and presentation.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 70676fee-41a8-4e13-a96c-a4253df1013a

📥 Commits

Reviewing files that changed from the base of the PR and between b8d1863 and 14c350a.

📒 Files selected for processing (18)

• docs/app/components/docs/toc.tsx
• docs/app/styles/docs.css
• docs/content/docs/architecture/job-lifecycle.mdx
• docs/content/docs/java/guides/core/index.mdx
• docs/content/docs/java/guides/reliability/index.mdx
• docs/content/docs/node/guides/core/index.mdx
• docs/content/docs/node/guides/reliability/index.mdx
• docs/content/docs/python/api-reference/overview.mdx
• docs/content/docs/python/api-reference/queue/events.mdx
• docs/content/docs/python/api-reference/queue/index.mdx
• docs/content/docs/python/api-reference/queue/jobs.mdx
• docs/content/docs/python/getting-started/quickstart.mdx
• docs/content/docs/python/guides/advanced-execution/index.mdx
• docs/content/docs/python/guides/core/index.mdx
• docs/content/docs/python/guides/extensibility/index.mdx
• docs/content/docs/python/guides/observability/index.mdx
• docs/content/docs/python/guides/reliability/index.mdx
• docs/content/docs/python/more/examples/index.mdx

💤 Files with no reviewable changes (16)

• docs/content/docs/python/getting-started/quickstart.mdx
• docs/content/docs/python/api-reference/overview.mdx
• docs/content/docs/node/guides/reliability/index.mdx
• docs/content/docs/python/api-reference/queue/events.mdx
• docs/content/docs/python/guides/observability/index.mdx
• docs/content/docs/python/api-reference/queue/index.mdx
• docs/content/docs/python/more/examples/index.mdx
• docs/content/docs/java/guides/core/index.mdx
• docs/content/docs/python/api-reference/queue/jobs.mdx
• docs/content/docs/python/guides/core/index.mdx
• docs/content/docs/python/guides/reliability/index.mdx
• docs/content/docs/architecture/job-lifecycle.mdx
• docs/content/docs/java/guides/reliability/index.mdx
• docs/content/docs/python/guides/extensibility/index.mdx
• docs/content/docs/python/guides/advanced-execution/index.mdx
• docs/content/docs/node/guides/core/index.mdx

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📝 Walkthrough

Walkthrough

The documentation updates add automatic numbering to top-level TOC entries, prevent duplicate authored heading numbers, consolidate page descriptions into metadata, and replace selected introductory text with structured components or callouts.

Changes

Documentation navigation and content

Layer / File(s)	Summary
TOC numbering docs/app/components/docs/toc.tsx, docs/app/styles/docs.css	Top-level TOC links receive CSS-generated section numbers, while numeric prefixes are stripped from H2 link text before rendering.
Introductory metadata cleanup docs/content/docs/java/..., docs/content/docs/node/..., docs/content/docs/python/...	Duplicated introductory sentences are removed from multiple pages, with selected descriptions updated in frontmatter.
Structured page introductions docs/content/docs/architecture/job-lifecycle.mdx, docs/content/docs/python/api-reference/queue/index.mdx	The lifecycle page renders JobStateMachine, and the queue API page adds an informational callout listing its sub-pages.

Estimated code review effort: 2 (Simple) | ~10 minutes

Suggested labels: docs

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately summarizes the two main docs changes: deduplicating lead paragraphs and adding On this page TOC numbering.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch docs/toc-and-lead-dedup

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