feat: complete dev_tools module self-containment

Migrate dev_tools module to self-contained structure:

- routes/api/ - API endpoints
- models/architecture_scan.py - Architecture scan models
- models/test_run.py - Test run models
- schemas/ - Pydantic schemas
- services/ - Business logic services
- tasks/ - Celery background tasks
- exceptions.py - Module exceptions

Updated definition.py with self-contained paths.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

app/modules/dev_tools/tasks/__init__.py

@@ -0,0 +1,18 @@
+# app/modules/dev_tools/tasks/__init__.py
+"""
+Dev-Tools module Celery tasks.
+
+On-demand tasks for:
+- Code quality scans (architecture, security, performance)
+- Test execution
+
+Note: These tasks are triggered on-demand, not scheduled.
+"""
+
+from app.modules.dev_tools.tasks.code_quality import execute_code_quality_scan
+from app.modules.dev_tools.tasks.test_runner import execute_test_run
+
+__all__ = [
+    "execute_code_quality_scan",
+    "execute_test_run",
+]