Phase 1: config loading, database migrations, audit log

- internal/config: TOML config with env overrides (MCR_ prefix),
  required field validation, same-filesystem check, defaults
- internal/db: SQLite via modernc.org/sqlite, WAL mode, 2 migrations
  (core registry tables + policy/audit), foreign key cascades
- internal/db: audit log write/list with filtering and pagination
- deploy/examples/mcr.toml: annotated example configuration
- .golangci.yaml: disable fieldalignment (readability over micro-opt)
- checkpoint skill copied from mcias

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

PROJECT_PLAN.md

@@ -9,8 +9,8 @@ design specification.
 
 | Phase | Description | Status |
 |-------|-------------|--------|
-| 0 | Project scaffolding | Not started |
-| 1 | Configuration & database | Not started |
+| 0 | Project scaffolding | **Complete** |
+| 1 | Configuration & database | **Complete** |
 | 2 | Blob storage layer | Not started |
 | 3 | MCIAS authentication | Not started |
 | 4 | Policy engine | Not started |