feat(credential): add env:// scheme for environment variable API keys

Allows api_key values like `env://OPENROUTER_API_KEY` to be resolved
from the process environment at startup, useful for container and CI
deployments where secrets are injected via env vars.

Also adds build-go target to web/Makefile, BUILD_TARGET arg to
docker/Dockerfile, and a new Dockerfile.launcher for building both
picoclaw and picoclaw-launcher into a single image.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

docker/Dockerfile.launcher

@@ -0,0 +1,64 @@
+# ============================================================
+# Stage 1: Build picoclaw binary (with WhatsApp native support)
+# ============================================================
+FROM golang:1.25-alpine AS picoclaw-builder
+
+RUN apk add --no-cache git make
+
+WORKDIR /src
+COPY go.mod go.sum ./
+RUN go mod download
+COPY . .
+ARG BUILD_TARGET=build-whatsapp-native-docker
+RUN make ${BUILD_TARGET}
+
+# ============================================================
+# Stage 2: Build picoclaw-launcher frontend
+# ============================================================
+FROM node:20-alpine AS frontend-builder
+
+RUN npm install -g pnpm
+
+WORKDIR /src/web/frontend
+COPY web/frontend/package.json web/frontend/pnpm-lock.yaml ./
+RUN pnpm install --frozen-lockfile
+
+COPY web/frontend/ ./
+RUN pnpm build:backend
+
+# ============================================================
+# Stage 3: Build picoclaw-launcher backend (embeds frontend)
+# ============================================================
+FROM golang:1.25-alpine AS launcher-builder
+
+RUN apk add --no-cache git make
+
+WORKDIR /src
+COPY go.mod go.sum ./
+RUN go mod download
+COPY . .
+COPY --from=frontend-builder /src/web/backend/dist /src/web/backend/dist
+RUN cd web && make build-go
+
+# ============================================================
+# Stage 4: Minimal runtime image
+# ============================================================
+FROM alpine:3.23
+
+RUN apk add --no-cache ca-certificates tzdata curl
+
+COPY --from=picoclaw-builder /src/build/picoclaw /usr/local/bin/picoclaw
+COPY --from=launcher-builder /src/web/build/picoclaw-launcher /usr/local/bin/picoclaw-launcher
+
+RUN addgroup -g 1000 picoclaw && \
+    adduser -D -u 1000 -G picoclaw picoclaw
+
+USER picoclaw
+
+RUN /usr/local/bin/picoclaw onboard
+
+HEALTHCHECK --interval=30s --timeout=3s --start-period=10s --retries=3 \
+  CMD wget -q --spider http://localhost:18800/ || exit 1
+
+ENTRYPOINT ["picoclaw-launcher"]
+CMD ["-public", "-no-browser", "-port", "18800"]

docs/credential_encryption.md

@@ -49,6 +49,7 @@ The same formats apply to both `api_key` (singular) and individual elements in t
 | Plaintext | `sk-abc123` | Used as-is |
 | File reference | `file://openai.key` | Content read from the same directory as the config file |
 | Encrypted | `enc://<base64>` | Decrypted at startup using `PICOCLAW_KEY_PASSPHRASE` |
+| Env var | `env://OPENROUTER_API_KEY` | Value read from the named environment variable at startup |
 | Empty | `""` | Passed through unchanged (used with `auth_method: oauth`) |
 
 ---

pkg/credential/credential.go

@@ -9,6 +9,7 @@
 //   - Plaintext:   "sk-abc123"          → returned as-is
 //   - File ref:    "file://filename.key" → content read from configDir/filename.key
 //   - Encrypted:   "enc://<base64>"     → AES-256-GCM decrypt via PICOCLAW_KEY_PASSPHRASE
+//   - Env var:     "env://VAR_NAME"     → value of the named environment variable
 //   - Empty:       ""                   → returned as-is (auth_method=oauth etc.)
 //
 // Encryption uses AES-256-GCM with HKDF-SHA256 key derivation (< 1ms, safe for embedded Linux).
@@ -77,6 +78,7 @@ const picoclawHome = "PICOCLAW_HOME"
 const (
 	FileScheme = "file://"
 	EncScheme  = "enc://"
+	envScheme  = "env://"
 
 	hkdfInfo = "picoclaw-credential-v1"
 	saltLen  = 16
@@ -107,6 +109,7 @@ func NewResolver(configDir string) *Resolver {
 //
 //   - ""                  → "" (no error; auth_method=oauth needs no key)
 //   - "file://name.key"   → trimmed content of configDir/name.key
+//   - "env://VAR_NAME"    → value of the named environment variable
 //   - anything else       → raw unchanged (plaintext credential)
 func (r *Resolver) Resolve(raw string) (string, error) {
 	if raw == "" {
@@ -149,6 +152,21 @@ func (r *Resolver) Resolve(raw string) (string, error) {
 		return resolveEncrypted(raw)
 	}
 
+	if strings.HasPrefix(raw, envScheme) {
+		varName := strings.TrimPrefix(raw, envScheme)
+		if varName == "" {
+			return "", fmt.Errorf("credential: env:// reference has no variable name")
+		}
+		val, ok := os.LookupEnv(varName)
+		if !ok {
+			return "", fmt.Errorf("credential: env:// variable %q is not set", varName)
+		}
+		if val == "" {
+			return "", fmt.Errorf("credential: env:// variable %q is empty", varName)
+		}
+		return val, nil
+	}
+
 	// Plaintext credential — return unchanged.
 	return raw, nil
 }

pkg/credential/credential_test.go

@@ -281,3 +281,40 @@ func TestEncrypt_SSHKeyOutsideAllowedDirs(t *testing.T) {
 		t.Fatal("expected error for SSH key outside allowed directories, got nil")
 	}
 }
+
+func TestResolve_EnvVar_Success(t *testing.T) {
+	t.Setenv("PICOCLAW_TEST_API_KEY", "sk-from-env")
+	r := credential.NewResolver(t.TempDir())
+	got, err := r.Resolve("env://PICOCLAW_TEST_API_KEY")
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if got != "sk-from-env" {
+		t.Fatalf("got %q, want %q", got, "sk-from-env")
+	}
+}
+
+func TestResolve_EnvVar_NotSet(t *testing.T) {
+	r := credential.NewResolver(t.TempDir())
+	_, err := r.Resolve("env://PICOCLAW_TEST_UNSET_VAR_XYZ")
+	if err == nil {
+		t.Fatal("expected error for unset env var, got nil")
+	}
+}
+
+func TestResolve_EnvVar_Empty(t *testing.T) {
+	t.Setenv("PICOCLAW_TEST_EMPTY_KEY", "")
+	r := credential.NewResolver(t.TempDir())
+	_, err := r.Resolve("env://PICOCLAW_TEST_EMPTY_KEY")
+	if err == nil {
+		t.Fatal("expected error for empty env var, got nil")
+	}
+}
+
+func TestResolve_EnvVar_NoVarName(t *testing.T) {
+	r := credential.NewResolver(t.TempDir())
+	_, err := r.Resolve("env://")
+	if err == nil {
+		t.Fatal("expected error for env:// with no variable name, got nil")
+	}
+}

web/Makefile

@@ -1,4 +1,4 @@
-.PHONY: dev dev-frontend dev-backend build build-frontend build-dev-picoclaw test lint clean
+.PHONY: dev dev-frontend dev-backend build build-frontend build-dev-picoclaw build-go test lint clean
 
 # Go variables
 GO?=CGO_ENABLED=0 go
@@ -106,6 +106,10 @@ build-dev-picoclaw:
 	@mkdir -p "$$(dirname "$(PICOCLAW_BINARY)")"
 	@$(GO) build $(GOFLAGS) -ldflags "$(LDFLAGS)" -o "$(PICOCLAW_BINARY)" ../cmd/picoclaw
 
+# Build only the Go binary (frontend dist must already exist)
+build-go:
+	${WEB_GO} build $(GOFLAGS) -ldflags "$(LDFLAGS)" -o $(BUILD_DIR)/picoclaw-launcher ./backend/
+
 # Run all tests
 test:
 	cd $(BACKEND_DIR) && ${WEB_GO} test ./...