chore: deprecate activityTasks and activities tables in postgres (CM-1007)

[themarolt]

Note

High Risk
High risk because it drops the Postgres activities tables and removes multiple code paths/scripts that referenced them; any remaining runtime dependency on these tables or the removed GET /activity/{id} endpoint will break after deployment/migration.

Overview
Deprecates Postgres-backed activities storage. Adds a migration that drops activityTasks and activities, and removes the GET /activity/{id} API plus related repository/service methods for reading/creating activities directly in Postgres.

Updates remaining code to stop depending on the dropped tables (e.g., member identity conflict checks now use memberSegments), removes affiliation logic that updated activities.organizationId, and deletes several legacy maintenance scripts and old data-access helpers/queries that read/write from activities (including email-worker “top activity types” and data-sink-worker activity repo/columns).

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[Copilot]

Pull request overview

This PR removes remaining Postgres dependencies on the legacy activities/activityTasks tables and introduces a migration to drop those tables from the backend database schema.

Changes:

• Drop activities and activityTasks tables via a new migration, and remove related legacy repositories/helpers.
• Remove multiple Postgres-based helper queries/mutations around activities in the data-access layer and backend repositories.
• Adjust member-erasure and affiliation logic to no longer touch the removed activities table.

Reviewed changes

Copilot reviewed 6 out of 9 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
services/libs/data-access-layer/src/old/apps/data_sink_worker/repo/activity.repo.ts	Deletes the legacy Postgres activities repository implementation.
services/libs/data-access-layer/src/old/apps/data_sink_worker/repo/activity.data.ts	Removes legacy ColumnSet builders tied to Postgres activities inserts/updates.
services/libs/data-access-layer/src/activities/sql.ts	Removes Postgres-only helper functions (by-id fetch, member flags update, conversation link, sentiment/type aggregations).
services/apps/data_sink_worker/src/bin/erase-member.ts	Stops attempting to delete from the activities table during member erasure.
backend/src/database/repositories/memberSegmentAffiliationRepository.ts	Removes write/update paths that were updating activities.organizationId.
backend/src/database/repositories/memberRepository.ts	Replaces a segment lookup from activities with a lookup from memberSegments during identity conflict handling.
backend/src/database/migrations/V1778146717__drop-activities-and-activity-tasks.sql	Adds migration to drop activityTasks and activities.
backend/src/database/migrations/U1778146717__drop-activities-and-activity-tasks.sql	Adds an undo migration file (currently empty).
backend/src/bin/scripts/fix-auto-merged-orgs.ts	Removes a backend script that directly updated Postgres activities.

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[cursor]

Cursor Bugbot has reviewed your changes and found 1 potential issue.

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[Copilot]

Pull request overview

Copilot reviewed 6 out of 9 changed files in this pull request and generated 1 comment.

Comments suppressed due to low confidence (1)

backend/src/database/repositories/memberSegmentAffiliationRepository.ts:88

• In destroyAll(), the raw DELETE FROM "memberSegmentAffiliations" ... query is executed with type: QueryTypes.SELECT. This is inconsistent with other repositories (which use QueryTypes.DELETE) and can lead to incorrect result handling. Change the query type to QueryTypes.DELETE (or omit type if you rely on metadata).

  override async destroyAll(ids: string[]): Promise<void> {
    const transaction = this.transaction

    const records = await this.findInIds(ids)