feat(release): add macOS binary notarization via goreleaser (#1274)

Add notarize.macos section to .goreleaser.yaml using anchore/quill
for cross-platform code signing and Apple notarization of darwin
binaries. Covers all three build targets (picoclaw, picoclaw-launcher,
picoclaw-launcher-tui).

Notarization is gated on MACOS_SIGN_P12 being set, so releases
without the secrets configured will skip this step gracefully.

Required GitHub secrets:
- MACOS_SIGN_P12: base64-encoded .p12 certificate
- MACOS_SIGN_PASSWORD: certificate password
- MACOS_NOTARY_ISSUER_ID: App Store Connect issuer UUID
- MACOS_NOTARY_KEY_ID: App Store Connect API key ID
- MACOS_NOTARY_KEY: base64-encoded .p8 API key

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

.github/workflows/release.yml

@@ -96,6 +96,11 @@ jobs:
           GITHUB_REPOSITORY_OWNER: ${{ github.repository_owner }}
           DOCKERHUB_IMAGE_NAME: ${{ vars.DOCKERHUB_REPOSITORY }}
           GOVERSION: ${{ steps.setup-go.outputs.go-version }}
+          MACOS_SIGN_P12: ${{ secrets.MACOS_SIGN_P12 }}
+          MACOS_SIGN_PASSWORD: ${{ secrets.MACOS_SIGN_PASSWORD }}
+          MACOS_NOTARY_ISSUER_ID: ${{ secrets.MACOS_NOTARY_ISSUER_ID }}
+          MACOS_NOTARY_KEY_ID: ${{ secrets.MACOS_NOTARY_KEY_ID }}
+          MACOS_NOTARY_KEY: ${{ secrets.MACOS_NOTARY_KEY }}
 
       - name: Apply release flags
         shell: bash

.goreleaser.yaml

@@ -124,6 +124,23 @@ dockers_v2:
       - linux/arm64
       - linux/riscv64
 
+notarize:
+  macos:
+    - enabled: '{{ isEnvSet "MACOS_SIGN_P12" }}'
+      ids:
+        - picoclaw
+        - picoclaw-launcher
+        - picoclaw-launcher-tui
+      sign:
+        certificate: "{{.Env.MACOS_SIGN_P12}}"
+        password: "{{.Env.MACOS_SIGN_PASSWORD}}"
+      notarize:
+        issuer_id: "{{.Env.MACOS_NOTARY_ISSUER_ID}}"
+        key_id: "{{.Env.MACOS_NOTARY_KEY_ID}}"
+        key: "{{.Env.MACOS_NOTARY_KEY}}"
+        wait: true
+        timeout: 20m
+
 archives:
   - formats: [tar.gz]
     # this name template makes the OS and Arch compatible with the results of `uname`.