chore(schema): migrate to GORM V2 with multi-database support

- [x] Implement GORM V2 metadata store with SQLite, PostgreSQL, and MySQL support
- [x] Add database migration system using gormigrate for schema versioning
- [x] Create migration CLI tool with support for migrate, rollback, and status commands
- [x] Add Docker support for migration container (Dockerfile.migrate)
- [x] Implement automatic partition management for PostgreSQL time-series tables
- [x] Add background aggregation worker for download statistics
- [x] Support connection pooling configuration (max_open_conns, max_idle_conns, conn_max_lifetime)
- [x] Add blocking mechanism based on vulnerability thresholds in stats and handlers
- [x] Update Helm charts with migration init containers and multi-database configuration
- [x] Replace deprecated SQLite store with optimized GORM implementation
- [x] Add comprehensive integration tests for MySQL and PostgreSQL
- [x] Update frontend to display blocked packages and storage utilization
- [x] Add goreleaser configuration for migrate binary and container image
- [x] Update configuration examples with database backend options and recommendations

.goreleaser.yaml

@@ -32,6 +32,24 @@ builds:
       - -X github.com/lukaszraczylo/gohoarder/internal/version.GitCommit={{.ShortCommit}}
       - -X github.com/lukaszraczylo/gohoarder/internal/version.BuildTime={{.Date}}
 
+  - id: migrate
+    main: ./cmd/migrate
+    binary: migrate
+    env:
+      - CGO_ENABLED=0
+    goos:
+      - linux
+      - darwin
+      - windows
+    goarch:
+      - amd64
+      - arm64
+    ldflags:
+      - -s -w
+      - -X main.Version={{.Version}}
+      - -X main.GitCommit={{.ShortCommit}}
+      - -X main.BuildTime={{.Date}}
+
 # Archives for releases
 archives:
   - id: default
@@ -182,6 +200,28 @@ dockers_v2:
       org.opencontainers.image.created: "{{ .Date }}"
       org.opencontainers.image.revision: "{{ .FullCommit }}"
 
+  # 5. Migration Engine - Database migration tool
+  - id: gohoarder-migrate
+    ids:
+      - migrate
+    images:
+      - ghcr.io/lukaszraczylo/gohoarder-migrate
+    tags:
+      - "{{ .Version }}"
+      - latest
+    platforms:
+      - linux/amd64
+      - linux/arm64
+    dockerfile: Dockerfile.migrate
+    labels:
+      org.opencontainers.image.title: GoHoarder Migrate
+      org.opencontainers.image.description: Database migration tool for GoHoarder V2 schema
+      org.opencontainers.image.url: https://github.com/lukaszraczylo/gohoarder
+      org.opencontainers.image.source: https://github.com/lukaszraczylo/gohoarder
+      org.opencontainers.image.version: "{{ .Version }}"
+      org.opencontainers.image.created: "{{ .Date }}"
+      org.opencontainers.image.revision: "{{ .FullCommit }}"
+
 # Artifact signing with cosign
 signs:
   - cmd: cosign