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

Dockerfile

@@ -1,23 +1,20 @@
-FROM git.unkin.net/unkin/almalinux9-base:latest
+FROM golang:1.25-alpine AS builder
 
-ARG VERSION=0.0.0.dev0
+RUN apk add --no-cache git
 
-COPY . /build
+WORKDIR /build
 
-RUN HATCH_VCS_PRETEND_VERSION=${VERSION} \
-    SETUPTOOLS_SCM_PRETEND_VERSION=${VERSION} \
-    uv build --wheel --directory /build && \
-    useradd -m -r -s /bin/sh appuser
+COPY go.mod go.sum ./
+RUN go mod download
 
-USER appuser
-RUN uv tool install --from /build/dist/*.whl artifactapi
+COPY . .
 
-USER root
-RUN rm -rf /build
+RUN CGO_ENABLED=0 go build -ldflags="-s -w" -o artifactapi ./cmd/artifactapi
+
+FROM gcr.io/distroless/static-debian12:nonroot
+
+COPY --from=builder /build/artifactapi /usr/local/bin/artifactapi
 
 EXPOSE 8000
-HEALTHCHECK --interval=30s --timeout=10s --start-period=5s --retries=3 CMD curl -f http://localhost:8000/health || exit 1
-USER appuser
-ENV PATH="/home/appuser/.local/bin:$PATH"
-WORKDIR /app
-CMD ["artifactapi"]
+
+ENTRYPOINT ["artifactapi"]