Add release infrastructure and complete implementation

- Dockerfile: distroless container for MCP server
- GoReleaser: multi-platform binary and Docker builds with cosign signing
- GitHub Actions: release workflow using shared actions
- Semver config for automatic version calculation
- Persistence layer, content indexing, and improved tool handlers

.github/workflows/release.yaml

@@ -0,0 +1,20 @@
+name: Release
+
+on:
+  push:
+    branches:
+      - main
+
+permissions:
+  contents: write
+  packages: write
+  id-token: write
+
+jobs:
+  release:
+    uses: lukaszraczylo/shared-actions/.github/workflows/go-release.yaml@main
+    with:
+      go-version: ">=1.24"
+      docker-enabled: true
+      docker-registry: ghcr.io
+    secrets: inherit