Module possession trend charts — Schema Approval Follow-up

[Polyterative]

Module Possession Trend Charts — Schema Approval Follow-up

Problem

Static module possession counts are now public-safe, but trend charts require historical aggregate data that does not exist yet.

Goals

• Decide whether daily aggregate snapshots are the right historical data model.
• Get explicit human approval before any Supabase schema, migration, scheduled function, RLS, or generated-type work.
• After approval, render a lightweight collapsed trend surface on module detail pages.

Assumptions

• Option B from the completed static-count plan remains preferred: daily aggregate snapshots avoid per-user event history.
• Agents may inspect and draft proposals, but must not apply migrations/RLS/policies without explicit approval.

MVP / Structural / Polish layers

MVP

• Confirm product owner wants trend charts now.
• Draft the proposed module_possession_snapshots schema and scheduled snapshot strategy.
• Request explicit approval before applying any database changes.

Structural

• After approval, read the schema-change preflight in internaldocs/patterns/BACKEND_METHODS.md.
• Apply approved migration/RLS/scheduled-function changes.
• Run pnpm updateBackendTypes.
• Add SupabaseService read methods and cache keys for trend snapshots.

Polish

• Add a collapsed trend chart/toggle on module details.
• Hide weak-signal or sparse chart data rather than showing fake precision.
• Validate responsive visual treatment with the UI debug screenshot workflow.

File-level checklist

• internaldocs/patterns/BACKEND_METHODS.md — read schema-change preflight before SQL.
• Supabase migration/RLS/scheduled function — approval required before changes.
• src/backend/database.types.ts — refresh only after approved schema work.
• src/app/features/backend/DatabaseStrings.ts / supabase-queries.ts — add approved read path.
• Module detail UI/specs — render approved trend surface.

Acceptance criteria

• No autonomous schema/RLS/migration work happens before explicit human approval.
• Approved trend data is aggregate-only and does not expose per-user history.
• Trend charts are hidden or collapsed by default and do not overwhelm module details.

Validation strategy

• Approved schema work: pnpm updateBackendTypes.
• Targeted module detail/backend tests.
• node scripts/checks/check-docs.cjs.
• pnpm lint.

Decision log

• 2026-06-18T10:40+02:00 — Split from the completed static-count loop because historical trend snapshots require explicit schema/migration approval.
  Source: internaldocs/workflow/plans/module-possession-trend-charts-schema-followup.md
  Migration status: migrated from local documentation