Add HandleGetModules returning module state, metadata, and
public config (auth providers, Create URI scheme). No auth
required — clients call this pre-login.
Register at /api/modules before the auth middleware.
Ref #97
Add modules.Registry and config.Config fields to Server struct.
Create registry in main.go, load state from YAML+DB, log all
module states at startup.
Conditionally start job/runner sweeper goroutines only when the
jobs module is enabled.
Update all 5 test files to pass registry to NewServer.
Ref #95, #96
Add migration 016 with two tables for the module system:
- settings_overrides: dotted-path config overrides set via admin UI
- module_state: per-module enabled/disabled state
Update testutil.TruncateAll to include new tables.
Ref #94