Rename update_at to updated_at in messages_by_room schema

[ngangwar962]

Summary

• Renamed update_at to updated_at in the messages_by_room Cassandra table schema
• Fixes inconsistency with thread_messages_by_room and pinned_messages_by_room which already use updated_at

Test plan

• Verified no Go source files reference update_at — change is schema doc only
• Confirmed thread_messages_by_room and pinned_messages_by_room already use updated_at

https://claude.ai/code/session_016Sx3S4ueP9Ef1MvtGQ97NR

Summary by CodeRabbit

Release Notes

• Documentation
  • Updated database schema documentation to standardize timestamp column naming across message storage tables, enhancing consistency in the message infrastructure.

[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: 7eb8b48e-ae89-4059-a795-88ef1ece0b3a

📥 Commits

Reviewing files that changed from the base of the PR and between f8d4bda and cd9d23a.

📒 Files selected for processing (1)

• docs/cassandra_message_model.md

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📝 Walkthrough

Walkthrough

The Cassandra message table schema documentation was updated to rename the timestamp column from update_at to updated_at in the messages_by_room table, aligning it with naming conventions used in other related tables.

Changes

Cohort / File(s)	Summary
Schema documentation docs/cassandra_message_model.md	Renamed timestamp column update_at to updated_at in the messages_by_room table for consistency with other message-related table schemas.

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~2 minutes

Possibly related PRs

• chore:add cassandra message schema documentation #22: Introduced the original update_at column in the messages_by_room schema; this PR corrects the naming to match the convention used in other message tables.

Suggested reviewers

• mliu33

Poem

🐰 A typo hopped away today,
update_at could not stay,
Now updated_at takes its place,
Consistency wins the race! ✨

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately reflects the main change: renaming the update_at column to updated_at in the messages_by_room schema, which is the primary objective of this pull request.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch claude/rename-cassandra-field-HvB5D

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