Closes#39
Splits the Dockerfile into a dedicated lint stage using the `golangci/golangci-lint` image directly, rather than copying the binary into the builder stage.
## Changes
### Dockerfile
- **Lint stage** (`AS lint`): Uses the pre-built `golangci/golangci-lint` image (pinned by sha256) to run `make fmt-check` and `make lint`. This is a self-contained stage with its own `go mod download` and source copy.
- **Builder stage** (`AS builder`): Runs only `make test` and the final binary build. No longer needs golangci-lint installed.
- **Stage dependency**: `COPY --from=lint /src/go.sum /dev/null` forces BuildKit to always execute the lint stage (without this, unused stages are silently skipped).
- Both stages touch `mfer/mf.pb.go` to prevent make from trying to regenerate via protoc.
With BuildKit, the lint and builder stages run in parallel after their shared `go mod download` layers complete, so lint/formatting failures surface much faster without blocking on test execution.
### Makefile
- Added `lint` to the `check` target prereqs: `check: test lint fmt-check` (was `check: test fmt-check`), matching the [REPO_POLICIES](https://git.eeqj.de/sneak/prompts/raw/branch/main/prompts/REPO_POLICIES.md) requirement.
Co-authored-by: clawbot <clawbot@noreply.git.eeqj.de>
Reviewed-on: #45
Co-authored-by: clawbot <clawbot@noreply.example.org>
Co-committed-by: clawbot <clawbot@noreply.example.org>
- Add --sign-key flag and MFER_SIGN_KEY env var to gen and freshen commands
- Sign inner message multihash with GPG detached signature
- Include signer fingerprint and public key in outer wrapper
- Add comprehensive tests with temporary GPG keyring
- Increase test timeout to 10s for GPG key generation
Changed the default behavior to exclude dotfiles (files/dirs starting with .)
which is the more common use case. Added --include-dotfiles flag for when
hidden files need to be included in the manifest.
