feat: Adds four backend features to bring comments to audit parity with posts, aggregate a personalized fan feed, implement the favorites API the frontend already calls, and expose Stellar network config for client discovery.

[Emeka000]

Changes

• Comments soft-delete + audit (Backend: Add comment soft-delete and audit parity with posts #1434): deletedAt/deletedBy added to Comment; new CommentAuditLog entity + migration; CommentsService.remove() now soft-deletes, writes an audit row, and emits CommentDeletedEvent; all reads filter deletedAt IS NULL; hard delete kept as a separate, non-default hardDelete() method — mirrors the existing Post/PostAuditLog pattern exactly.
• Personalized fan feed (Backend: Add personalized fan feed endpoint #1435): new feed module — GET /v1/feed/subscriptions (JWT-required, cursor-paginated). SubscriptionsService.getActiveCreatorIdsForFan() resolves the fan's actively-subscribed creators; PostsService.findFeed() returns their published, non-deleted posts via keyset (createdAt+id) cursor pagination. Empty subscriptions → empty page, not an error.
• Favorites API (Backend: Implement favorites API matching frontend contract #1436): new favorites module — Favorite entity (unique on userId+creatorId), migration, service, and controller matching the existing frontend contract in frontend/src/lib/favorites.ts (GET /v1/favorites → creator ID array, POST/DELETE /v1/favorites/:creatorId). Add is idempotent; missing target creator → 404; listing is always scoped to the caller's own userId.
• Network discovery config (Backend: Add GET /config/network for Stellar network discovery #1437): new config module — public GET /v1/config/network returning network, networkPassphrase, horizonUrl, rpcUrl derived from STELLAR_NETWORK/env overrides (same passphrase-mapping convention as subscription-chain-reader.service.ts). No secrets in the response.
• Wired FeedModule, FavoritesModule, and NetworkConfigModule into AppModule; registered the two new migrations in migration.datasource.ts.

Test Plan

Automated tests added or updated

• Unit tests (backend/src/**/*.spec.ts) — comments.service.spec.ts rewritten for soft-delete/audit/event behavior; posts.service.spec.ts extended with findFeed cursor/filter cases; subscriptions.service.spec.ts extended with getActiveCreatorIdsForFan; new specs for feed.service, feed.controller, favorites.service, favorites.controller, network-config.service, network-config.controller.
• Integration / e2e tests — not added; existing modules follow the same unit-test-only convention (repos mocked via getRepositoryToken), and AppModule has no TypeOrmModule.forRoot wired yet (pre-existing, see Notes).
• Frontend tests — no frontend changes.
• Contract tests — no contract changes.

How to run the tests locally

cd backend && npm install   # not run in this session — see Notes
npm test
Manual verification checklist
 Happy path works end-to-end in a local environment
 Error / edge cases handled gracefully
 No regressions in closely related API or UI flows
 Rate-limiting, auth guards, and feature flags behave as expected where touched
 Linting passes: cd backend && npm run lint
Related issues
Closes #1434, #1435, #1436, #1437

Notes for reviewers
Dependencies were not installed and the build/test suite was not run in this session (per task constraints) — please run npm install && npm test && npm run lint before merging.
Two pre-existing gaps, unrelated to this PR, worth a follow-up ticket: (1) PostsModule, CommentsModule, and LikesModule were already not imported into AppModule before this change; (2) there is no TypeOrmModule.forRoot(...) anywhere in AppModule — only migration.datasource.ts configures a real Postgres connection for the migration CLI. Neither was introduced or worsened here.
contract/Cargo.lock shows as locally modified but was not touched by this work — worth checking before commit/push.

closes #1435 
Closes #1434
closes  #1436
 closes  #1437

[drips-wave]

@Emeka000 Great news! 🎉 Based on an automated assessment of this PR, the linked Wave issue(s) no longer count against your application limits.

You can now already apply to more issues while waiting for a review of this PR. Keep up the great work! 🚀

Learn more about application limits