Feat/v3 go rewrite (#47)

Complete rewrite of ArtifactAPI from Python/FastAPI to Go as a single binary.

Core engine:
- 10 package providers: generic, docker, helm, pypi, npm, rpm, alpine,
  puppet, terraform, goproxy — each with built-in mutable patterns
- Content-addressable storage (SHA256 dedup across all remotes)
- Three-tier caching: Redis (TTL/locks) → S3/MinIO (blobs) → upstream
- Classifier with allowlist/blocklist per-remote (empty = allow all)
- Circuit breaker, conditional revalidation, stale-on-error
- Background garbage collection for orphaned blobs
- Access logging to PostgreSQL

API:
- v1 proxy endpoints (backwards compatible)
- v2 management API: CRUD remotes/virtuals, object browser, stats,
  health, SSE events, probe/test endpoint
- Virtual repos with index merging (Helm YAML + PyPI HTML)

Frontend (React + Vite, separate Dockerfile):
- Dashboard with stats, health indicators, top remotes
- Remotes list with type filter, remote detail with config/patterns
- Object browser with pagination and evict
- Test Remote page: probe any remote path, see headers/size/timing
- Virtuals page with expandable member lists

TUI (Bubble Tea):
- Dashboard, remotes list/detail, object browser, virtuals
- Vim-style navigation, artifactapi tui --endpoint <url>

Infrastructure:
- S3 client supports MinIO, Ceph RGW, AWS S3 (minio-go)
- PostgreSQL schema with migrations
- Docker Compose: API + UI + Postgres 17 + Redis 7 + MinIO
- Makefile with Go version check, build/test/lint/fmt/e2e targets
- Distroless Docker image (~15MB)

Testing:
- Unit tests for models, classifier, providers, mergers
- E2E tests with testcontainers-go (real Postgres/Redis/MinIO)

Terraform config:
- All 40 production remotes + helm virtual as HCL
- Provider repo: terraform-provider-artifactapi v0.0.1 (separate)

---------

Co-authored-by: Ben Vincent <ben@unkin.net>
Reviewed-on: #47

internal/database/virtuals.go

@@ -0,0 +1,64 @@
+package database
+
+import (
+	"context"
+
+	"git.unkin.net/unkin/artifactapi/pkg/models"
+)
+
+func (db *DB) GetVirtual(ctx context.Context, name string) (*models.Virtual, error) {
+	row := db.Pool.QueryRow(ctx, `
+		SELECT name, package_type, description, members, managed_by, created_at, updated_at
+		FROM virtuals WHERE name = $1
+	`, name)
+
+	var v models.Virtual
+	err := row.Scan(&v.Name, &v.PackageType, &v.Description, &v.Members, &v.ManagedBy, &v.CreatedAt, &v.UpdatedAt)
+	if err != nil {
+		return nil, err
+	}
+	return &v, nil
+}
+
+func (db *DB) ListVirtuals(ctx context.Context) ([]models.Virtual, error) {
+	rows, err := db.Pool.Query(ctx, `
+		SELECT name, package_type, description, members, managed_by, created_at, updated_at
+		FROM virtuals ORDER BY name
+	`)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	var virtuals []models.Virtual
+	for rows.Next() {
+		var v models.Virtual
+		if err := rows.Scan(&v.Name, &v.PackageType, &v.Description, &v.Members, &v.ManagedBy, &v.CreatedAt, &v.UpdatedAt); err != nil {
+			return nil, err
+		}
+		virtuals = append(virtuals, v)
+	}
+	return virtuals, rows.Err()
+}
+
+func (db *DB) CreateVirtual(ctx context.Context, v *models.Virtual) error {
+	_, err := db.Pool.Exec(ctx, `
+		INSERT INTO virtuals (name, package_type, description, members, managed_by)
+		VALUES ($1, $2, $3, $4, $5)
+	`, v.Name, v.PackageType, v.Description, v.Members, v.ManagedBy)
+	return err
+}
+
+func (db *DB) UpdateVirtual(ctx context.Context, v *models.Virtual) error {
+	_, err := db.Pool.Exec(ctx, `
+		UPDATE virtuals SET
+			package_type=$2, description=$3, members=$4, managed_by=$5, updated_at=NOW()
+		WHERE name=$1
+	`, v.Name, v.PackageType, v.Description, v.Members, v.ManagedBy)
+	return err
+}
+
+func (db *DB) DeleteVirtual(ctx context.Context, name string) error {
+	_, err := db.Pool.Exec(ctx, `DELETE FROM virtuals WHERE name = $1`, name)
+	return err
+}