Feat/schema learning in process

[tonyalaribe]

Closes #

How to test

Checklist

• Make sure you have described your changes and added all relevant screenshots or data.
• Make sure your changes are tested (stories and/or unit, integration, or end-to-end tests).
• Make sure to add/update documentation regarding your changes (or request one from the team).
• You are NOT deprecating/removing a feature.

[claude]

Code Review

What this PR does

Fixes a broken SQL query in projectCacheById caused by migration 0090_drop_legacy_schema_tables.sql, which drops apis.field_category via DROP TYPE … CASCADE. That cascade also drops the field_category column from projects.redacted_fields, making the old rf.field_category reference invalid. The fix hardcodes an empty second segment so the three-part <>-delimited format is preserved.

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Issues

1. Outdated struct/comment — Projects.hs:334-335

The doc comment still says:

-- [endpointHash]<>[field_category eg requestBody]<>[field_key_path]
-- Those redact fields that don't have endpoint or field_category attached, would be applied to every endpoint and field category.

field_category no longer exists. The comment should be updated to reflect that the middle segment is always empty now — otherwise future readers will think the format is still meaningful.

2. Overly verbose SQL comment

The added SQL comment spans three lines explaining the migration context. Given the project's preference for conciseness, a single line is sufficient:

-- field_category col dropped by 0090 CASCADE; middle segment is always empty now.

3. concat call can be simplified

concat(rf.endpoint_hash,'<>','<>', rf.path)

concat with three literal string arguments is slightly indirect. The intent is clearer as:

concat(rf.endpoint_hash, '<><>', rf.path)

Both are equivalent (PostgreSQL concat is NULL-safe for the hash), but the two-arg form is more readable.

4. No test/CI coverage for the affected query

The PR checklist has all items unchecked, and there's no test exercising projectCacheById against a schema that has field_category dropped. Given this was a silent runtime crash before the fix, a regression test here would prevent recurrence.

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Non-issues

• The NULL-safety of concat vs. || is correctly preserved — rf.endpoint_hash can be NULL (global redactions), and concat treats NULL as empty string, which is the desired behaviour.
• Preserving the three-segment format is correct: downstream consumers (redactJSON + any split-on-<> callers) won't need changes.