Tasks — Remediation Plan History

Task 1: Create migration for compliance_item_history table [Requirement 2, 7]

Create backend/migrations/add_compliance_item_history.js with the schema from the design doc
[~] Table: compliance_item_history (id, hostname, field_name, old_value, new_value, change_reason, changed_by, changed_at)
[~] Add CHECK constraint on field_name: IN ('resolution_date', 'remediation_plan')
[~] Add index on (hostname, field_name)
[~] Add index on (changed_at)
[~] Register in migrations/run-all.js
[~] Run migration and verify table exists

[~] In backend/routes/compliance.js, locate the PATCH metadata handler
[~] Accept new optional change_reason field (max 500 chars, validated)
[~] Before updating compliance_items, SELECT current resolution_date and remediation_plan for the hostname
[~] For each field where old !== new, INSERT into compliance_item_history (hostname, field_name, old_value, new_value, change_reason, changed_by)
[~] Skip history insert if old === new (no-op changes)
[~] Wrap history insert + item update in a transaction
[~] Handle NULL → value and value → NULL transitions
[~] Add audit log entry with old/new values
[~] Verify existing response shape is preserved

[~] In the existing /items/:hostname handler, add a query: SELECT id, field_name, old_value, new_value, change_reason, changed_by, changed_at FROM compliance_item_history WHERE hostname = $1 ORDER BY changed_at DESC LIMIT 10
[~] Add history array to the response object
[~] If query fails, return empty array (graceful degradation) and log error
[~] Verify response includes history alongside existing metrics and notes

[~] In the bulk update flow (POST /vcl/bulk-commit), before updating each hostname's resolution_date or remediation_plan, query current values
[~] For each changed field, INSERT into compliance_item_history with changed_by = req.user.username
[~] Skip if value is unchanged
[~] No change_reason for bulk updates (set to NULL)

[~] Add changeReason state and a single-line text input between the Save button and Notes section
[~] Pass change_reason in the PATCH request body when saving
[~] Clear changeReason after successful save
[~] Add "Change History" section below the remediation plan area
[~] Fetch history from the GET /items/:hostname response
[~] Display entries: field icon, old → new, username, date, reason (if present)
[~] Resolution dates formatted as YYYY-MM-DD, NULL shown as "—"
[~] Remediation plan values truncated to 60 chars with title tooltip
[~] Show "No changes recorded" when history is empty
[~] Run npm run build after changes

[~] Confirm burndown query in vclMultiVertical.js reads from compliance_items.resolution_date only
[~] Confirm donut query uses MAX(resolution_date) grouped by hostname
[~] Set a resolution date, change it multiple times, verify device appears once in burndown
[~] No code changes expected — verification only