Search: Remove shard/replica settings for serverless compatibility

[reakaleek]

What

Remove number_of_shards and number_of_replicas settings from the content date lookup index creation request.

Why

Elasticsearch serverless mode does not support these settings — the platform manages shard/replica counts automatically. Including them causes a 400 error on index creation, breaking the assembler index pipeline.

How

Removed the settings block from the PUT index request in ContentDateEnrichment.EnsureLookupIndexAsync. The mappings-only request is sufficient.

Test plan

• Verify the assembler index CI job passes against the serverless cluster
• Confirm the docs-assembler-content-dates-edge index is created successfully

🤖 Generated with Claude Code

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No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro Plus

Run ID: 6cbc384a-8b57-4ec5-bac6-9fe423908429

📥 Commits

Reviewing files that changed from the base of the PR and between 0490b6f and 8b2e64e.

📒 Files selected for processing (1)

• src/Elastic.Markdown/Exporters/Elasticsearch/ContentDateEnrichment.cs

💤 Files with no reviewable changes (1)

• src/Elastic.Markdown/Exporters/Elasticsearch/ContentDateEnrichment.cs

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📝 Walkthrough

Walkthrough

The change removes explicit settings configuration from the Elasticsearch index creation payload in the EnsureLookupIndexAsync method. Specifically, the number_of_shards (1) and number_of_replicas (0) settings are no longer explicitly specified when creating the lookup index. The index existence check, PUT request, success handling, and logging flow remain unchanged. The mappings configuration is unaffected by this modification.

Suggested labels

fix

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately describes the main change: removing shard/replica settings for Elasticsearch serverless compatibility.
Description check	✅ Passed	The description is directly related to the changeset, clearly explaining what was removed, why it was necessary, and the testing approach.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

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✨ Finishing Touches

✨ Simplify code

• Create PR with simplified code
• Commit simplified code in branch confusion-bubbler

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