feat: two-phase migrations, DB settings loading in create_app

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

fablednetmon/core/migration_runner.py

@@ -1,3 +1,4 @@
+# fablednetmon/core/migration_runner.py
 from __future__ import annotations
 import logging
 from pathlib import Path
@@ -5,13 +6,26 @@ from pathlib import Path
 logger = logging.getLogger(__name__)
 
 
-def run_migrations(db_url: str, plugin_migration_dirs: list[Path] | None = None) -> None:
-    """Run core + plugin Alembic migrations synchronously.
+def run_core_migrations(db_url: str) -> None:
+    """Run only core Alembic migrations (no plugin dirs).
 
-    Called during create_app() before the event loop starts.
-    Applies all pending migrations in dependency order.
-    Plugin migration dirs are included via Alembic's version_locations.
+    Called first so the app_settings table exists before loading settings.
     """
+    _run(db_url, plugin_migration_dirs=[])
+
+
+def run_plugin_migrations(db_url: str, plugin_migration_dirs: list[Path]) -> None:
+    """Run plugin Alembic migrations after settings are loaded."""
+    if plugin_migration_dirs:
+        _run(db_url, plugin_migration_dirs=plugin_migration_dirs)
+
+
+def run_migrations(db_url: str, plugin_migration_dirs: list[Path] | None = None) -> None:
+    """Run core + plugin Alembic migrations (single-phase convenience wrapper)."""
+    _run(db_url, plugin_migration_dirs=plugin_migration_dirs or [])
+
+
+def _run(db_url: str, plugin_migration_dirs: list[Path]) -> None:
     from alembic import command
     from alembic.config import Config
 
@@ -22,9 +36,8 @@ def run_migrations(db_url: str, plugin_migration_dirs: list[Path] | None = None)
     cfg.set_main_option("script_location", str(core_migrations))
     cfg.set_main_option("sqlalchemy.url", db_url)
 
-    # Build version_locations: core + any plugin version directories
     version_locs = [str(core_versions)]
-    for plugin_dir in (plugin_migration_dirs or []):
+    for plugin_dir in plugin_migration_dirs:
         pv = plugin_dir / "versions"
         if pv.exists():
             version_locs.append(str(pv))
@@ -37,12 +50,7 @@ def run_migrations(db_url: str, plugin_migration_dirs: list[Path] | None = None)
 
 
 def get_plugin_migration_dirs(plugin_dir: Path, plugins_cfg: dict) -> list[Path]:
-    """Return migration directories for all enabled plugins that have one.
-
-    Does not import any Python code — filesystem scan only.
-    Used to collect migration dirs before importing plugins, so migrations
-    can run before plugin Python code is loaded.
-    """
+    """Return migration directories for enabled plugins (filesystem scan only)."""
     dirs = []
     for name, cfg in plugins_cfg.items():
         if not cfg.get("enabled", False):