Close duplicate and OBEd open issues — add CHANGELOG issue references

[Copilot]

Reviewed all 51 open issues and identified 7 already-resolved (OBEd) issues and 3 duplicate issues. Added explicit issue-number references to the relevant CHANGELOG entries so maintainers can close them.

Proposed Changes:

1. Add Closes #110 to [Unreleased] hashing entry — collectionUniqueIndexID lowercases+hashes collection IDs, fixing uppercase index name failures
2. Add Closes #45 to v2.0.0 SNS entry — sns.js + ingest.publishResultsToSns() fully implements the requested SNS publishing with bbox/datetime/collection attributes
3. Add Closes #220, #234 to v2.0.0 stream-removal entry — sequential ingest replaced the stream that autocreated indices without custom mappings
4. Add Closes #363 to v2.0.0 type-detection entry — isCollection/isItem use type field, not heuristics
5. Add Closes #291 to v3.2.0 error-handling entry — database-client.js replaces the old esClient.js code that incorrectly attributed all index-creation errors to "already exists"
6. Fix typo indicies → indices in the touched CHANGELOG line

Also identified (no code change needed — close manually):

• Duplicates: Add STAC Collection and STAC Item spec validation to ingest #1039 and POST and PUT endpoints should validate Item before inserting into elasticsearch #211 are duplicates of Ingestion should validate a minimally-valid stac item or collection #303 (STAC validation at ingest; Ingestion should validate a minimally-valid stac item or collection #303 has the priority label); Transactions Extension for Collections? #195 is superseded by the more specific Implement Collection Transaction Extension #745 (Collection Transaction Extension)
• OBEd with no CHANGELOG gap: should item ingest fail if the collection has not been created? #364 — item ingest already throws InvalidIngestError if the collection index doesn't exist

PR Checklist:

• I have added my changes to the CHANGELOG or a CHANGELOG entry is not required.

Original prompt

review all open issues and see if any are suitable for closure due to being a duplicate or OBEd.

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[theodorehreuter]

Validated that problems in #220 have been resolved and closed it out

[naterubin]

Verified the other suggestions for duplicate and OBE issues and closed them as appropriate.

[matthewhanson]

Closed out remaining PRs that had been fixed but not closed.