feat(messages): add message_attachments migration

database/migrations/081_message_attachments.sql

@@ -0,0 +1,19 @@
+-- Migration: 081_message_attachments.sql
+-- Description: Create message_attachments table for file attachments in messaging
+-- Date: 2026-03-11
+
+CREATE TABLE IF NOT EXISTS message_attachments (
+    id SERIAL PRIMARY KEY,
+    message_id INTEGER NOT NULL REFERENCES private_messages(id) ON DELETE CASCADE,
+    filename VARCHAR(255) NOT NULL,
+    stored_filename VARCHAR(255) NOT NULL,
+    file_size INTEGER NOT NULL,
+    mime_type VARCHAR(100) NOT NULL,
+    created_at TIMESTAMP DEFAULT NOW()
+);
+
+CREATE INDEX idx_message_attachments_message_id ON message_attachments(message_id);
+
+-- Permissions
+GRANT ALL ON TABLE message_attachments TO nordabiz_app;
+GRANT USAGE, SELECT ON SEQUENCE message_attachments_id_seq TO nordabiz_app;