feat: add RPM packaging with nfpm and Gitea registry publishing

Bundles the CLI into a standalone binary via bun compile, packages
as RPM with nfpm, and publishes to Gitea's built-in package registry.
Users install with: dnf config-manager --add-repo <gitea>/rpm.repo

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

nfpm.yaml

@@ -0,0 +1,12 @@
+name: mcpctl
+arch: amd64
+version: 0.1.0
+release: "1"
+maintainer: michal
+description: kubectl-like CLI for managing MCP servers
+license: MIT
+contents:
+  - src: ./dist/mcpctl
+    dst: /usr/bin/mcpctl
+    file_info:
+      mode: 0755