feat: add dedicated brain database connection for remote MariaDB

Brain memories can now be stored in a separate database, co-located
with Qdrant vectors on the homelab. Defaults to the app's main DB
when no BRAIN_DB_* env vars are set (zero-config for existing installs).

- Add brain.database config with BRAIN_DB_* env var support
- Register 'brain' database connection in Boot.php
- Set BrainMemory model to use 'brain' connection
- Update BrainService transactions to use brain connection
- Update migration to use brain connection, drop workspace FK
  (cross-database FKs not supported)
- Add migration to drop FK on existing installs
- Update default URLs from *.lthn.lan to *.lthn.sh

Co-Authored-By: Virgil <virgil@lethean.io>

Boot.php

@@ -71,6 +71,14 @@ class Boot extends ServiceProvider
             'agentic'
         );
 
+        // Register the dedicated brain database connection.
+        // Falls back to the app's default DB when no BRAIN_DB_* env vars are set.
+        $brainDb = config('mcp.brain.database');
+
+        if (is_array($brainDb) && ! empty($brainDb['host'])) {
+            config(['database.connections.brain' => $brainDb]);
+        }
+
         $this->app->singleton(\Core\Mod\Agentic\Services\AgenticManager::class);
 
         $this->app->singleton(\Core\Mod\Agentic\Services\BrainService::class, function ($app) {

Migrations/0001_01_01_000008_create_brain_memories_table.php

@@ -8,20 +8,26 @@ use Illuminate\Support\Facades\Schema;
 
 return new class extends Migration
 {
+    /** Use the dedicated brain connection so the table lands in the right database. */
+    protected $connection = 'brain';
+
     /**
      * Create brain_memories table for OpenBrain shared knowledge store.
      *
      * Guarded with hasTable() so this migration is idempotent and
      * can coexist with the consolidated app-level migration.
+     *
+     * No FK to workspaces — the brain database may be remote and
+     * the workspaces table only exists in the app database.
      */
     public function up(): void
     {
-        Schema::disableForeignKeyConstraints();
+        $schema = Schema::connection($this->getConnection());
 
-        if (! Schema::hasTable('brain_memories')) {
-            Schema::create('brain_memories', function (Blueprint $table) {
+        if (! $schema->hasTable('brain_memories')) {
+            $schema->create('brain_memories', function (Blueprint $table) {
                 $table->uuid('id')->primary();
-                $table->foreignId('workspace_id')->constrained()->cascadeOnDelete();
+                $table->unsignedBigInteger('workspace_id');
                 $table->string('agent_id', 64);
                 $table->string('type', 32)->index();
                 $table->text('content');
@@ -44,14 +50,10 @@ return new class extends Migration
                     ->nullOnDelete();
             });
         }
-
-        Schema::enableForeignKeyConstraints();
     }
 
     public function down(): void
     {
-        Schema::disableForeignKeyConstraints();
-        Schema::dropIfExists('brain_memories');
-        Schema::enableForeignKeyConstraints();
+        Schema::connection($this->getConnection())->dropIfExists('brain_memories');
     }
 };

Migrations/0001_01_01_000009_drop_brain_memories_workspace_fk.php

@@ -0,0 +1,41 @@
+<?php
+
+declare(strict_types=1);
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+/**
+ * Drop the workspace_id foreign key from brain_memories.
+ *
+ * The brain database may be remote (co-located with Qdrant on the homelab),
+ * so cross-database FK constraints to the app's workspaces table are not
+ * possible. The column stays as a plain indexed integer.
+ */
+return new class extends Migration
+{
+    protected $connection = 'brain';
+
+    public function up(): void
+    {
+        $schema = Schema::connection($this->getConnection());
+
+        if (! $schema->hasTable('brain_memories')) {
+            return;
+        }
+
+        $schema->table('brain_memories', function (Blueprint $table) {
+            try {
+                $table->dropForeign(['workspace_id']);
+            } catch (\Throwable) {
+                // FK doesn't exist — fresh install, nothing to drop.
+            }
+        });
+    }
+
+    public function down(): void
+    {
+        // Not re-adding the FK — it was only valid when brain and app shared a database.
+    }
+};

Models/BrainMemory.php

@@ -51,6 +51,8 @@ class BrainMemory extends Model
         'architecture',
     ];
 
+    protected $connection = 'brain';
+
     protected $table = 'brain_memories';
 
     protected $fillable = [

Services/BrainService.php

@@ -75,7 +75,7 @@ class BrainService
     {
         $vector = $this->embed($attributes['content']);
 
-        return DB::transaction(function () use ($attributes, $vector) {
+        return DB::connection('brain')->transaction(function () use ($attributes, $vector) {
             $memory = BrainMemory::create($attributes);
 
             $payload = $this->buildQdrantPayload($memory->id, [
@@ -156,7 +156,7 @@ class BrainService
      */
     public function forget(string $id): void
     {
-        DB::transaction(function () use ($id) {
+        DB::connection('brain')->transaction(function () use ($id) {
             BrainMemory::where('id', $id)->delete();
             $this->qdrantDelete([$id]);
         });

config.php

@@ -82,10 +82,26 @@ return [
     */
 
     'brain' => [
-        'ollama_url' => env('BRAIN_OLLAMA_URL', 'https://ollama.lthn.lan'),
-        'qdrant_url' => env('BRAIN_QDRANT_URL', 'https://qdrant.lthn.lan'),
+        'ollama_url' => env('BRAIN_OLLAMA_URL', 'https://ollama.lthn.sh'),
+        'qdrant_url' => env('BRAIN_QDRANT_URL', 'https://qdrant.lthn.sh'),
         'collection' => env('BRAIN_COLLECTION', 'openbrain'),
         'embedding_model' => env('BRAIN_EMBEDDING_MODEL', 'embeddinggemma'),
+
+        // Dedicated database connection for brain_memories.
+        // Defaults to the app's main database when BRAIN_DB_* env vars are absent.
+        // Set BRAIN_DB_HOST to a remote MariaDB (e.g. the homelab) to co-locate
+        // DB rows with their Qdrant vectors.
+        'database' => [
+            'driver' => env('BRAIN_DB_DRIVER', env('DB_CONNECTION', 'mariadb')),
+            'host' => env('BRAIN_DB_HOST', env('DB_HOST', '127.0.0.1')),
+            'port' => env('BRAIN_DB_PORT', env('DB_PORT', '3306')),
+            'database' => env('BRAIN_DB_DATABASE', env('DB_DATABASE', 'forge')),
+            'username' => env('BRAIN_DB_USERNAME', env('DB_USERNAME', 'forge')),
+            'password' => env('BRAIN_DB_PASSWORD', env('DB_PASSWORD', '')),
+            'charset' => 'utf8mb4',
+            'collation' => 'utf8mb4_unicode_ci',
+            'prefix' => '',
+        ],
     ],
 
 ];