feat: implement ntfy-discord bridge in Go

- SSE subscription to ntfy with auto-reconnect
- Discord webhook integration with embed formatting
- Priority to color mapping, tag to emoji conversion
- Native HashiCorp Vault support (Kubernetes + token auth)
- Hot reload secrets via fsnotify or Vault polling
- Prometheus metrics (/metrics endpoint)
- Health/ready endpoints for Kubernetes probes
- Comprehensive unit tests and fuzz tests
- Multi-stage Docker build (~10MB scratch image)
- CI/CD pipeline for Gitea Actions

.gitignore

@@ -0,0 +1,30 @@
+# Binaries
+ntfy-discord
+*.exe
+*.exe~
+*.dll
+*.so
+*.dylib
+
+# Test binary
+*.test
+
+# Output of the go coverage tool
+*.out
+
+# Dependency directories
+vendor/
+
+# IDE
+.idea/
+.vscode/
+*.swp
+*.swo
+
+# OS
+.DS_Store
+Thumbs.db
+
+# Local env files
+.env
+.env.local