feat(release): add GoReleaser config and Homebrew tap support

Enable `brew install multica-cli` via multica-ai/homebrew-tap.
GoReleaser builds cross-platform binaries (macOS/Linux, amd64/arm64)
and auto-updates the Homebrew formula on tagged releases.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.github/workflows/release.yml

@@ -0,0 +1,33 @@
+name: Release
+
+on:
+  push:
+    tags:
+      - "v*"
+
+permissions:
+  contents: write
+
+jobs:
+  release:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v6
+        with:
+          fetch-depth: 0
+
+      - name: Setup Go
+        uses: actions/setup-go@v5
+        with:
+          go-version: "1.24"
+          cache-dependency-path: server/go.sum
+
+      - name: Run GoReleaser
+        uses: goreleaser/goreleaser-action@v6
+        with:
+          version: "~> v2"
+          args: release --clean
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          HOMEBREW_TAP_GITHUB_TOKEN: ${{ secrets.HOMEBREW_TAP_GITHUB_TOKEN }}

.goreleaser.yml

@@ -0,0 +1,55 @@
+version: 2
+
+project_name: multica-cli
+
+before:
+  hooks:
+    - cd server && go mod tidy
+
+builds:
+  - id: multica-cli
+    main: ./cmd/multica
+    dir: server
+    binary: multica-cli
+    ldflags:
+      - -s -w
+      - -X main.version={{.Version}}
+      - -X main.commit={{.ShortCommit}}
+    env:
+      - CGO_ENABLED=0
+    goos:
+      - darwin
+      - linux
+    goarch:
+      - amd64
+      - arm64
+
+archives:
+  - id: default
+    formats:
+      - tar.gz
+    name_template: "{{ .ProjectName }}_{{ .Os }}_{{ .Arch }}"
+
+checksum:
+  name_template: "checksums.txt"
+
+changelog:
+  sort: asc
+  filters:
+    exclude:
+      - "^docs:"
+      - "^test:"
+      - "^chore:"
+
+homebrew_casks:
+  - name: multica-cli
+    binaries:
+      - multica-cli
+    repository:
+      owner: multica-ai
+      name: homebrew-tap
+      branch: main
+      token: "{{ .Env.HOMEBREW_TAP_GITHUB_TOKEN }}"
+    directory: Formula
+    homepage: "https://github.com/multica-ai/super-multica"
+    description: "Multica CLI — local agent runtime and management tool for the Multica platform"