docs(v2): add Examples showcase, and make the examples runnable

[scarmuega]

What

Adds an Examples section to the v2 docs that showcases the ready-to-run
configs under examples/, and fixes the examples themselves so that
following the docs verbatim actually works.

Docs

• New docs/v2/examples/ section (_meta.yaml + index.mdx): how to run an
  example, companion-file/setup notes, categorized index of every example
  (sources, filters, sinks, cursors, observability, library), and a few inlined
  end-to-end recipes.
• Cross-link from the v2 introduction.

Example fixes

Validated by building v2.1.0 from source and running every example.

• Dead relay swept (21 configs + 2 inlined recipes). The examples pointed at
  relays-new.cardano-mainnet.iohk.io:3001, which no longer resolves
  (NXDOMAIN) — run verbatim they only looped on error connecting bearer. Now
  they use the live backbone.mainnet.cardanofoundation.org:3001.
• dolos_source (broken → fixed). The U5C source's metadata field is
  required (no serde default), so the example failed to load with
  missing field metadata. Added an empty metadata table, pointed the URL at a
  local Dolos, and documented the Demeter API-key pattern.
• hydra source (panic → graceful). bootstrap called
  .expect("Can't connect"), so an unreachable Hydra node panicked the process.
  It now logs the error and returns a retryable WorkerError, like the rest of
  the source.

Not included

• examples/pool_metadata still uses the removed Deno filter (separate
  removal/port decision) and is excluded from the showcase.
• Dead-relay references outside the examples (other docs pages, CONTRIBUTING.md,
  v1 docs) are left for a follow-up.

🤖 Generated with Claude Code

Summary by CodeRabbit

• Documentation

  • Added comprehensive examples documentation with setup guidance and categorized example descriptions.
  • Added Examples section to main documentation.

• Configuration

  • Updated all example peer endpoints to new Cardano Foundation backbone.
  • Dolos example now uses local gRPC endpoint by default.

• Bug Fixes

  • Improved Hydra WebSocket connection error handling to prevent panics.

[coderabbitai]

Caution

Review failed

Pull request was closed or merged during review

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: 51ccf33b-0484-44fe-a780-3e2cbd50ad06

📥 Commits

Reviewing files that changed from the base of the PR and between f0ee7d9 and b3d8ba8.

📒 Files selected for processing (26)

• docs/v2/examples/_meta.yaml
• docs/v2/examples/index.mdx
• docs/v2/index.mdx
• examples/assert/daemon.toml
• examples/aws_lambda/daemon.toml
• examples/aws_s3/daemon.toml
• examples/aws_sqs/daemon.toml
• examples/dolos_source/daemon.toml
• examples/elasticsearch/daemon.toml
• examples/file_cursor/daemon.toml
• examples/file_rotate/daemon.toml
• examples/gcp_cloudfunction/daemon.toml
• examples/gcp_pubsub/daemon.toml
• examples/into_json/daemon.toml
• examples/kafka/daemon.toml
• examples/metrics/daemon.toml
• examples/parse_cbor/daemon.toml
• examples/postgresql/daemon.toml
• examples/rabbitmq/daemon.toml
• examples/redis/daemon.toml
• examples/select/daemon.toml
• examples/stdout/daemon.toml
• examples/wasm_basic/daemon.toml
• examples/webhook_basics/daemon.toml
• examples/zeromq/daemon.toml
• src/sources/hydra.rs

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📝 Walkthrough

Walkthrough

Adds a new docs/v2/examples/ documentation section with an index page containing categorized example tables, setup instructions, and three TOML pipeline recipes. Updates the N2N peers endpoint in all 22 example daemon.toml files to backbone.mainnet.cardanofoundation.org:3001. Adjusts the dolos_source config to a local gRPC URL. Replaces a panic with logged error propagation in the Hydra WebSocket source.

Changes

Examples Documentation and Configuration

Layer / File(s)	Summary
Examples documentation page and navigation docs/v2/examples/_meta.yaml, docs/v2/examples/index.mdx, docs/v2/index.mdx	Adds _meta.yaml nav settings (label, order, collapsed), creates the full index.mdx with running instructions, categorized tables (Sources, Filters & pipelines, Sinks, Cursors, Observability), library section, and three complete TOML recipe snippets; links the new page from the v2 main index.
Bulk peer endpoint update across example configs examples/dolos_source/daemon.toml, examples/assert/daemon.toml, examples/aws_lambda/daemon.toml, examples/aws_s3/daemon.toml, examples/aws_sqs/daemon.toml, examples/elasticsearch/daemon.toml, examples/file_cursor/daemon.toml, examples/file_rotate/daemon.toml, examples/gcp_cloudfunction/daemon.toml, examples/gcp_pubsub/daemon.toml, examples/into_json/daemon.toml, examples/kafka/daemon.toml, examples/metrics/daemon.toml, examples/parse_cbor/daemon.toml, examples/postgresql/daemon.toml, examples/rabbitmq/daemon.toml, examples/redis/daemon.toml, examples/select/daemon.toml, examples/stdout/daemon.toml, examples/wasm_basic/daemon.toml, examples/webhook_basics/daemon.toml, examples/zeromq/daemon.toml	All N2N peers entries are changed from relays-new.cardano-mainnet.iohk.io:3001 to backbone.mainnet.cardanofoundation.org:3001; dolos_source additionally switches url to http://localhost:50051 and adds an empty metadata = {} field with gRPC header comments.

Hydra WebSocket Error Handling

Layer / File(s)	Summary
Hydra WebSocket graceful error handling src/sources/hydra.rs	Replaces connect_async(url).await.expect(...) with inspect_err-based tracing::error! logging and .or_restart()? propagation so connection failures trigger a restart instead of a panic.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Poem

🐇 Hop hop, the backbone now leads the way,
No more old relays to cause dismay!
New docs appear with tables and tips,
While Hydra no longer panics and flips.
A restart instead, a graceful retreat—
The rabbit approves: these changes are neat! 🌟

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately describes the main change: adding documentation for the Examples section and making example configurations executable.
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.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ 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/v2-examples-showcase

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