azure: add blob index tags support for blob storage output

[fredmeltwater]

Summary

• Adds a new tags field to the azure_blob_storage output, allowing users to set blob index tags as key/value
  pairs with interpolation support
• Tags are applied atomically on block blob uploads and via SetTags for append blobs
• Enforces Azure's 10-tag limit at config parse time
• review skill used on this PR

Closes #2904

Test plan

• go build ./internal/impl/azure/... passes
• go test ./internal/impl/azure/... -short passes
• Integration test blob_storage_tags validates tags are set correctly on block blobs via Azurite

🤖 Generated with Claude Code

[meltwater-coreplatform]

Commits

LGTM

Review

Clean implementation adding blob index tags support to the azure_blob_storage output. Tags are parsed at config time as an InterpolatedStringMap with a 10-tag limit (matching Azure's constraint), deterministically sorted, and resolved per-message. Block blobs pass tags via UploadStreamOptions; append blobs set tags at creation via CreateOptions and update them on subsequent appends via SetTags. Integration test validates tag roundtrip through Azurite.

LGTM

[CLAassistant]

All committers have signed the CLA.

[fredmeltwater]

Hi @Jeffail this has been open for a few weeks — would love a review when you get a
chance

[josephwoodward]

Hi @fredmeltwater, are you able to run task docs on this to generate the new docs?

[fredmeltwater]

Hi @josephwoodward were you able to take a look?

[VictorErmakov]

Just a bump for this PR. We are really looking into it