refactor: restructure build/release/sdk into pkg/ layout

Moves build/, release/, sdk/ into pkg/ following Go convention.
Updates import paths in cmd/ci and cmd/sdk.

Co-Authored-By: Virgil <virgil@lethean.io>

CLAUDE.md

@@ -1,37 +1,84 @@
 # CLAUDE.md
 
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
 ## Project Overview
 
-`core/go-build` is the build system, release pipeline, and SDK generation tool. Three main packages: build (cross-compilation, archiving, signing), release (versioning, changelog, publishers), and sdk (OpenAPI diff, code generation).
+`core/go-build` is the build system, release pipeline, and SDK generation tool for the Core ecosystem. Three subsystems under `pkg/` — **build**, **release**, **sdk** — can be used as libraries or wired together via CLI commands in `cmd/`. This repo produces no standalone binary; `cmd/` packages register commands via `cli.RegisterCommands()` in `init()` functions, compiled into the `core` binary from `forge.lthn.ai/core/cli`.
 
-## Build & Development
+## Build & Test
 
 ```bash
-go test ./...
-go build ./...
+go build ./...                                          # compile all packages
+go test ./...                                           # run all tests
+go test ./pkg/build/... -run TestLoadConfig_Good        # single test by name
+go test -race ./...                                     # with race detection
 ```
 
+**Go workspace**: this module is part of `~/Code/go.work`. Run `go work sync` after cloning. Set `GOPRIVATE=forge.lthn.ai/*` for private module fetching.
+
 ## Architecture
 
-- `build/` — Build config (.core/build.yaml), project discovery, archiving, checksums
-- `build/builders/` — Go, Wails, Docker, LinuxKit, C++, Taskfile builders
-- `build/signing/` — Code signing (macOS notarisation, GPG)
-- `build/buildcmd/` — CLI commands for `core build`
-- `release/` — Versioning, changelog generation, release orchestration
-- `release/publishers/` — GitHub, Homebrew, Scoop, AUR, npm, Docker, Chocolatey
-- `sdk/` — OpenAPI spec diffing, SDK code generation
-- `cmd/ci/` — CI/release pipeline commands
-- `cmd/sdk/` — SDK validation commands
+The three subsystems share common types but are independent:
 
-## Dependencies
+- **`pkg/build/`** — Config loading (`.core/build.yaml`), project discovery via marker files, `Builder` interface, archiving (tar.gz/zip), checksums (SHA-256)
+- **`pkg/build/builders/`** — Go, Wails, Docker, LinuxKit, C++, Taskfile builder implementations
+- **`pkg/build/signing/`** — `Signer` interface with GPG, macOS codesign/notarisation, Windows (placeholder). Credentials support `$ENV` expansion
+- **`pkg/release/`** — Version resolution from git tags, conventional-commit changelog generation, release orchestration. Two entry points: `Run()` (full pipeline) and `Publish()` (pre-built artifacts from `dist/`)
+- **`pkg/release/publishers/`** — `Publisher` interface: GitHub, Docker, npm, Homebrew, Scoop, AUR, Chocolatey, LinuxKit
+- **`pkg/sdk/`** — OpenAPI spec detection, breaking-change diff via oasdiff, SDK code generation
+- **`pkg/sdk/generators/`** — `Generator` interface with registry. TypeScript, Python, Go, PHP generators (native tool -> npx -> Docker fallback)
+- **`cmd/build/`** — `core build` commands (build, from-path, pwa, sdk, release)
+- **`cmd/ci/`** — `core ci` commands (publish, init, changelog, version)
+- **`cmd/sdk/`** — `core sdk` commands (diff, validate)
 
-- `cli` — Command registration
-- `go-io` — File utilities
-- `go-i18n` — Internationalisation
-- `go-log` — Structured logging
-- Borg — Compression
-- kin-openapi, oasdiff — OpenAPI tooling
+### Key Data Flow
+
+```
+.core/build.yaml -> LoadConfig() -> BuildConfig
+project dir      -> Discover()   -> ProjectType -> getBuilder() -> Builder.Build() -> []Artifact
+                                    -> SignBinaries() -> ArchiveAll() -> ChecksumAll() -> Publisher.Publish()
+```
+
+### Key Interfaces
+
+- `build.Builder` — `Name()`, `Detect(fs, dir)`, `Build(ctx, cfg, targets)`
+- `publishers.Publisher` — `Name()`, `Publish(ctx, release, pubCfg, relCfg, dryRun)`
+- `signing.Signer` — `Name()`, `Available()`, `Sign(ctx, fs, path)`
+- `generators.Generator` — `Language()`, `Generate(ctx, opts)`, `Available()`, `Install()`
+
+### Filesystem Abstraction
+
+All file operations use `io.Medium` from `forge.lthn.ai/core/go-io`. Production uses `io.Local`; tests inject mocks for isolation.
+
+### Configuration Files
+
+- `.core/build.yaml` — Build config (targets, flags, signing)
+- `.core/release.yaml` — Release config (publishers, changelog, SDK settings)
 
 ## Coding Standards
 
-- UK English, strict types, testify, EUPL-1.2
+- **UK English** in comments and strings (colour, organisation, notarisation)
+- **Strict types** — all parameters and return types explicitly typed
+- **Error wrapping** — `fmt.Errorf("package.Function: message: %w", err)`
+- **testify** (`assert`/`require`) for assertions
+- **Test naming** — `_Good` (happy path), `_Bad` (expected errors), `_Ugly` (edge cases)
+- **Conventional commits** — `type(scope): description`
+- **Licence** — EUPL-1.2
+
+## Extension Points
+
+**New builder**: implement `build.Builder` in `pkg/build/builders/`, add to `getBuilder()` in `cmd/build/cmd_project.go` and `pkg/release/release.go`, optionally add `ProjectType` to `pkg/build/build.go` and marker to `pkg/build/discovery.go`.
+
+**New publisher**: implement `publishers.Publisher` in `pkg/release/publishers/`, add to `getPublisher()` in `pkg/release/release.go`, add config fields to `PublisherConfig` in `pkg/release/config.go` and `buildExtendedConfig()`.
+
+**New SDK generator**: implement `generators.Generator` in `pkg/sdk/generators/`, register in `pkg/sdk/sdk.go` `GenerateLanguage()`.
+
+## Dependencies
+
+- `forge.lthn.ai/core/cli` — Command registration (`cli.RegisterCommands`, `cli.Command`)
+- `forge.lthn.ai/core/go-io` — Filesystem abstraction (`io.Medium`, `io.Local`)
+- `forge.lthn.ai/core/go-i18n` — Internationalisation (`i18n.T()`, `i18n.Label()`)
+- `forge.lthn.ai/core/go-log` — Structured logging
+- `github.com/Snider/Borg` — XZ compression for archives
+- `github.com/getkin/kin-openapi` + `github.com/oasdiff/oasdiff` — OpenAPI parsing and diff

cmd/build/cmd_project.go

@@ -14,9 +14,9 @@ import (
 	"runtime"
 	"strings"
 
-	"forge.lthn.ai/core/go-build/build"
-	"forge.lthn.ai/core/go-build/build/builders"
-	"forge.lthn.ai/core/go-build/build/signing"
+	"forge.lthn.ai/core/go-build/pkg/build"
+	"forge.lthn.ai/core/go-build/pkg/build/builders"
+	"forge.lthn.ai/core/go-build/pkg/build/signing"
 	"forge.lthn.ai/core/go-i18n"
 	"forge.lthn.ai/core/go-io"
 )
@@ -42,6 +42,9 @@ func runProjectBuild(ctx context.Context, buildType string, ciMode bool, targets
 	var projectType build.ProjectType
 	if buildType != "" {
 		projectType = build.ProjectType(buildType)
+	} else if buildCfg.Build.Type != "" {
+		// Use type from .core/build.yaml
+		projectType = build.ProjectType(buildCfg.Build.Type)
 	} else {
 		projectType, err = build.PrimaryType(fs, projectDir)
 		if err != nil {
@@ -117,6 +120,7 @@ func runProjectBuild(ctx context.Context, buildType string, ciMode bool, targets
 		Name:       binaryName,
 		Version:    buildCfg.Project.Name, // Could be enhanced with git describe
 		LDFlags:    buildCfg.Build.LDFlags,
+		CGO:        buildCfg.Build.CGO,
 		// Docker/LinuxKit specific
 		Dockerfile:     configPath, // Reuse for Dockerfile path
 		LinuxKitConfig: configPath,

cmd/build/cmd_release.go

@@ -9,7 +9,7 @@ import (
 	"forge.lthn.ai/core/cli/pkg/cli"
 	"forge.lthn.ai/core/go-log"
 	"forge.lthn.ai/core/go-i18n"
-	"forge.lthn.ai/core/go-build/release"
+	"forge.lthn.ai/core/go-build/pkg/release"
 )
 
 // Flag variables for release command

cmd/build/cmd_sdk.go

@@ -11,7 +11,7 @@ import (
 	"os"
 	"strings"
 
-	"forge.lthn.ai/core/go-build/sdk"
+	"forge.lthn.ai/core/go-build/pkg/sdk"
 	"forge.lthn.ai/core/go-i18n"
 )
 

cmd/ci/ci.go

@@ -9,7 +9,7 @@ import (
 
 	"forge.lthn.ai/core/cli/pkg/cli"
 	"forge.lthn.ai/core/go-i18n"
-	"forge.lthn.ai/core/go-build/release"
+	"forge.lthn.ai/core/go-build/pkg/release"
 )
 
 // Style aliases from shared

cmd/sdk/cmd.go

@@ -12,7 +12,7 @@ import (
 	"fmt"
 	"os"
 
-	"forge.lthn.ai/core/go-build/sdk"
+	"forge.lthn.ai/core/go-build/pkg/sdk"
 	"forge.lthn.ai/core/cli/pkg/cli"
 	"forge.lthn.ai/core/go-i18n"
 )

pkg/build/build.go

@@ -65,6 +65,8 @@ type Config struct {
 	Version string
 	// LDFlags are additional linker flags.
 	LDFlags []string
+	// CGO enables CGO for the build (required for Wails, FrankenPHP, etc).
+	CGO bool
 
 	// Docker-specific config
 	Dockerfile string            // Path to Dockerfile (default: Dockerfile)

pkg/build/builders/cpp.go

@@ -11,7 +11,7 @@ import (
 	"runtime"
 	"strings"
 
-	"forge.lthn.ai/core/go-build/build"
+	"forge.lthn.ai/core/go-build/pkg/build"
 	"forge.lthn.ai/core/go-io"
 )
 

pkg/build/builders/cpp_test.go

@@ -5,7 +5,7 @@ import (
 	"path/filepath"
 	"testing"
 
-	"forge.lthn.ai/core/go-build/build"
+	"forge.lthn.ai/core/go-build/pkg/build"
 	"forge.lthn.ai/core/go-io"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"

pkg/build/builders/docker.go

@@ -10,7 +10,7 @@ import (
 	"path/filepath"
 	"strings"
 
-	"forge.lthn.ai/core/go-build/build"
+	"forge.lthn.ai/core/go-build/pkg/build"
 	"forge.lthn.ai/core/go-io"
 )
 

pkg/build/builders/docker_test.go

@@ -5,7 +5,7 @@ import (
 	"path/filepath"
 	"testing"
 
-	"forge.lthn.ai/core/go-build/build"
+	"forge.lthn.ai/core/go-build/pkg/build"
 	"forge.lthn.ai/core/go-io"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"

pkg/build/builders/go.go

@@ -10,7 +10,7 @@ import (
 	"path/filepath"
 	"strings"
 
-	"forge.lthn.ai/core/go-build/build"
+	"forge.lthn.ai/core/go-build/pkg/build"
 	"forge.lthn.ai/core/go-io"
 )
 
@@ -110,7 +110,11 @@ func (b *GoBuilder) buildTarget(ctx context.Context, cfg *build.Config, target b
 	env := os.Environ()
 	env = append(env, fmt.Sprintf("GOOS=%s", target.OS))
 	env = append(env, fmt.Sprintf("GOARCH=%s", target.Arch))
-	env = append(env, "CGO_ENABLED=0") // CGO disabled by default for cross-compilation
+	if cfg.CGO {
+		env = append(env, "CGO_ENABLED=1")
+	} else {
+		env = append(env, "CGO_ENABLED=0")
+	}
 	cmd.Env = env
 
 	// Capture output for error messages

pkg/build/builders/go_test.go

@@ -7,7 +7,7 @@ import (
 	"runtime"
 	"testing"
 
-	"forge.lthn.ai/core/go-build/build"
+	"forge.lthn.ai/core/go-build/pkg/build"
 	"forge.lthn.ai/core/go-io"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"

pkg/build/builders/linuxkit.go

@@ -10,7 +10,7 @@ import (
 	"path/filepath"
 	"strings"
 
-	"forge.lthn.ai/core/go-build/build"
+	"forge.lthn.ai/core/go-build/pkg/build"
 	"forge.lthn.ai/core/go-io"
 )
 

pkg/build/builders/linuxkit_test.go

@@ -5,7 +5,7 @@ import (
 	"path/filepath"
 	"testing"
 
-	"forge.lthn.ai/core/go-build/build"
+	"forge.lthn.ai/core/go-build/pkg/build"
 	"forge.lthn.ai/core/go-io"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"

pkg/build/builders/taskfile.go

@@ -10,7 +10,7 @@ import (
 	"path/filepath"
 	"strings"
 
-	"forge.lthn.ai/core/go-build/build"
+	"forge.lthn.ai/core/go-build/pkg/build"
 	"forge.lthn.ai/core/go-io"
 )
 

pkg/build/builders/taskfile_test.go

@@ -5,7 +5,7 @@ import (
 	"path/filepath"
 	"testing"
 
-	"forge.lthn.ai/core/go-build/build"
+	"forge.lthn.ai/core/go-build/pkg/build"
 	"forge.lthn.ai/core/go-io"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"

pkg/build/builders/wails.go

@@ -9,7 +9,7 @@ import (
 	"path/filepath"
 	"strings"
 
-	"forge.lthn.ai/core/go-build/build"
+	"forge.lthn.ai/core/go-build/pkg/build"
 	"forge.lthn.ai/core/go-io"
 )
 
@@ -49,12 +49,15 @@ func (b *WailsBuilder) Build(ctx context.Context, cfg *build.Config, targets []b
 	isV3 := b.isWailsV3(cfg.FS, cfg.ProjectDir)
 
 	if isV3 {
-		// Wails v3 strategy: Delegate to Taskfile
+		// Wails v3 strategy: Delegate to Taskfile if present, otherwise use Go builder with CGO
 		taskBuilder := NewTaskfileBuilder()
 		if detected, _ := taskBuilder.Detect(cfg.FS, cfg.ProjectDir); detected {
 			return taskBuilder.Build(ctx, cfg, targets)
 		}
-		return nil, errors.New("wails v3 projects require a Taskfile for building")
+		// Fall back to Go builder — Wails v3 is just a Go project that needs CGO
+		cfg.CGO = true
+		goBuilder := NewGoBuilder()
+		return goBuilder.Build(ctx, cfg, targets)
 	}
 
 	// Wails v2 strategy: Use 'wails build'

pkg/build/builders/wails_test.go

@@ -8,7 +8,7 @@ import (
 	"runtime"
 	"testing"
 
-	"forge.lthn.ai/core/go-build/build"
+	"forge.lthn.ai/core/go-build/pkg/build"
 	"forge.lthn.ai/core/go-io"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"

pkg/build/config.go

@@ -8,7 +8,7 @@ import (
 	"os"
 	"path/filepath"
 
-	"forge.lthn.ai/core/go-build/build/signing"
+	"forge.lthn.ai/core/go-build/pkg/build/signing"
 	"forge.lthn.ai/core/go-io"
 	"gopkg.in/yaml.v3"
 )
@@ -48,6 +48,8 @@ type Project struct {
 
 // Build holds build-time settings.
 type Build struct {
+	// Type overrides project type auto-detection (e.g., "go", "wails", "docker").
+	Type string `yaml:"type"`
 	// CGO enables CGO for the build.
 	CGO bool `yaml:"cgo"`
 	// Flags are additional build flags (e.g., ["-trimpath"]).

pkg/release/publishers/aur.go

@@ -13,7 +13,7 @@ import (
 	"strings"
 	"text/template"
 
-	"forge.lthn.ai/core/go-build/build"
+	"forge.lthn.ai/core/go-build/pkg/build"
 	"forge.lthn.ai/core/go-io"
 )
 

pkg/release/publishers/chocolatey.go

@@ -13,7 +13,7 @@ import (
 	"strings"
 	"text/template"
 
-	"forge.lthn.ai/core/go-build/build"
+	"forge.lthn.ai/core/go-build/pkg/build"
 	"forge.lthn.ai/core/go-i18n"
 	"forge.lthn.ai/core/go-io"
 )

pkg/release/publishers/github_test.go

@@ -8,7 +8,7 @@ import (
 	"strings"
 	"testing"
 
-	"forge.lthn.ai/core/go-build/build"
+	"forge.lthn.ai/core/go-build/pkg/build"
 	"forge.lthn.ai/core/go-io"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"

pkg/release/publishers/homebrew.go

@@ -13,7 +13,7 @@ import (
 	"strings"
 	"text/template"
 
-	"forge.lthn.ai/core/go-build/build"
+	"forge.lthn.ai/core/go-build/pkg/build"
 	"forge.lthn.ai/core/go-io"
 )
 

pkg/release/publishers/homebrew_test.go

@@ -6,7 +6,7 @@ import (
 	"os"
 	"testing"
 
-	"forge.lthn.ai/core/go-build/build"
+	"forge.lthn.ai/core/go-build/pkg/build"
 	"forge.lthn.ai/core/go-io"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"

pkg/release/publishers/integration_test.go

@@ -8,7 +8,7 @@ import (
 	"path/filepath"
 	"testing"
 
-	"forge.lthn.ai/core/go-build/build"
+	"forge.lthn.ai/core/go-build/pkg/build"
 	"forge.lthn.ai/core/go-io"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"

pkg/release/publishers/publisher.go

@@ -4,7 +4,7 @@ package publishers
 import (
 	"context"
 
-	"forge.lthn.ai/core/go-build/build"
+	"forge.lthn.ai/core/go-build/pkg/build"
 	"forge.lthn.ai/core/go-io"
 )
 

pkg/release/publishers/scoop.go

@@ -13,7 +13,7 @@ import (
 	"strings"
 	"text/template"
 
-	"forge.lthn.ai/core/go-build/build"
+	"forge.lthn.ai/core/go-build/pkg/build"
 	"forge.lthn.ai/core/go-io"
 )
 

pkg/release/release.go

@@ -10,9 +10,9 @@ import (
 	"path/filepath"
 	"strings"
 
-	"forge.lthn.ai/core/go-build/build"
-	"forge.lthn.ai/core/go-build/build/builders"
-	"forge.lthn.ai/core/go-build/release/publishers"
+	"forge.lthn.ai/core/go-build/pkg/build"
+	"forge.lthn.ai/core/go-build/pkg/build/builders"
+	"forge.lthn.ai/core/go-build/pkg/release/publishers"
 	"forge.lthn.ai/core/go-io"
 )
 

pkg/release/release_test.go

@@ -7,7 +7,7 @@ import (
 	"path/filepath"
 	"testing"
 
-	"forge.lthn.ai/core/go-build/build"
+	"forge.lthn.ai/core/go-build/pkg/build"
 	"forge.lthn.ai/core/go-io"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"

pkg/release/sdk.go

@@ -6,7 +6,7 @@ import (
 	"errors"
 	"fmt"
 
-	"forge.lthn.ai/core/go-build/sdk"
+	"forge.lthn.ai/core/go-build/pkg/sdk"
 )
 
 // SDKRelease holds the result of an SDK release.

pkg/sdk/generation_test.go

@@ -6,7 +6,7 @@ import (
 	"path/filepath"
 	"testing"
 
-	"forge.lthn.ai/core/go-build/sdk/generators"
+	"forge.lthn.ai/core/go-build/pkg/sdk/generators"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )