feat: add module config and migrations auto-discovery infrastructure

Add self-contained configuration and migrations support for modules:

Config auto-discovery (app/modules/config.py):
- Modules can have config.py with Pydantic Settings
- Environment variables prefixed with MODULE_NAME_
- Auto-discovered via get_module_config()

Migrations auto-discovery:
- Each module has migrations/versions/ directory
- Alembic discovers module migrations automatically
- Naming convention: {module}_{seq}_{description}.py

New architecture rules (MOD-013 to MOD-015):
- MOD-013: config.py should export config/config_class
- MOD-014: Migrations must follow naming convention
- MOD-015: Migrations directory must have __init__.py

Created for all 11 self-contained modules:
- config.py placeholder files
- migrations/ directories with __init__.py files

Added core and tenancy module definitions for completeness.

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

app/modules/monitoring/config.py

@@ -0,0 +1,31 @@
+# app/modules/monitoring/config.py
+"""
+Module configuration.
+
+Environment-based configuration using Pydantic Settings.
+Settings are loaded from environment variables with MONITORING_ prefix.
+
+Example:
+    MONITORING_SETTING_NAME=value
+
+Usage:
+    from app.modules.monitoring.config import config
+    value = config.setting_name
+"""
+from pydantic_settings import BaseSettings
+
+
+class ModuleConfig(BaseSettings):
+    """Configuration for monitoring module."""
+
+    # Add module-specific settings here
+    # Example:
+    # api_timeout: int = 30
+    # batch_size: int = 100
+
+    model_config = {"env_prefix": "MONITORING_"}
+
+
+# Export for auto-discovery
+config_class = ModuleConfig
+config = ModuleConfig()

app/modules/monitoring/migrations/__init__.py

@@ -0,0 +1 @@
+"""Module migrations."""

app/modules/monitoring/migrations/versions/__init__.py

@@ -0,0 +1 @@
+"""Migration versions."""