Unit testing and close source sync

.github/workflows/test.yml

@@ -0,0 +1,25 @@
+name: Tests
+
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        node-version: [ '18', '20', '22', '24', 'latest' ]
+    name: Node ${{ matrix.node-version }}
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: ${{ matrix.node-version }}
+      # Native accelerators (zlib-sync, erlpack, ...) are optionalDependencies and may
+      # fail to build on newer Node; that does not fail the install. sqlite3 is required
+      # for the migration tests and builds here.
+      - run: npm install
+      - run: npm run test:unit

.gitignore

@@ -2,5 +2,6 @@
 /node_modules/
 /config/
 src/functions/scnx-integration.js
+instrument.js
 /.vscode/
 /.idea/

developer-docs/README.md

@@ -13,6 +13,8 @@ Start here if you want to add a new feature as a module:
 - [**Database models**](./database-models.md) - Sequelize `Model.init` pattern, `models-dir`, accessing models from
   events.
 - [**Localization**](./localization.md) - adding strings to `locales/en.json` and using `localize()`.
+- [**Nickname manager**](./nickname-manager.md) - the shared service for changing member nicknames without modules
+  fighting each other.
 
 ## Configuration schema
 
@@ -34,7 +36,7 @@ The string + embed format used in `allowEmbed` config fields. Canonical referenc
 
 ## Migration
 
-- [**Migration**](./migration.md) - upgrading between major bot versions.
+- [**Migration**](./migration.md) - writing database migrations so schema changes reach existing installs.
 
 ## Validation
 

developer-docs/database-models.md

@@ -65,18 +65,13 @@ All standard Sequelize methods are available: `findOne`, `findAll`, `findOrCreat
 
 ## Migrations
 
-The bot calls `sequelize.sync()` at startup, which creates missing tables and adds missing columns automatically. **It
-does not modify or remove existing columns.** If you change a column's type, rename it, or drop it, you have two
-options:
-
-1. **Manual migration.** Use Sequelize's [umzug](https://github.com/sequelize/umzug) or write SQL by hand. Drop the
-   bot's table or run `ALTER TABLE` against your database.
-2. **Bump the table name.** For breaking schema changes, rename `tableName` (e.g. `welcomer_User_v2`). The old table
-   stays in place for safety; you migrate data on the side.
-
-For non-trivial migrations across versions, the bot exposes `module.exports.migrationStart()` / `migrationEnd()` from
-`main.js` - call these around long-running migration code so SIGTERM/SIGINT defers shutdown until the migration
-finishes.
+The bot calls `sequelize.sync()` at startup, which creates missing **tables**. **It does not add columns to existing
+tables, nor modify or remove existing columns.** So whenever you add, rename, change, or drop a field on an existing
+model, ship a migration alongside it so existing installs pick up the schema change.
+
+Migrations are file-based and run automatically on boot by an [Umzug](https://github.com/sequelize/umzug)-based runner -
+you drop a file into your module's `migrations/` directory and the runner discovers it, applies it once, tracks it, and
+backs up the affected tables first. See [migration.md](./migration.md) for the full guide.
 
 ## Associations