feat: add Stalwart Mail Server and FoundationDB library packages

- add stalwart: main mail server with systemd integration and user management
- add stalwart-cli: command line interface tool for server administration
- add stalwart-foundationdb: FoundationDB-enabled version with proper dependencies
- add libfoundationdb: FoundationDB client library (libfdb_c.so) package

All packages include proper conflict resolution, systemd services, and follow
repository packaging conventions. stalwart and stalwart-foundationdb are
mutually exclusive to prevent installation conflicts.

rpms/libfoundationdb/resources/build.sh

@@ -0,0 +1,10 @@
+#!/usr/bin/bash
+
+# Download the required library
+curl -L -o /app/libfdb_c.so https://github.com/apple/foundationdb/releases/download/${PACKAGE_VERSION}/libfdb_c.x86_64.so
+
+# Make the library readable
+chmod 755 /app/libfdb_c.so
+
+# Build the RPM
+nfpm pkg --config /app/resources/nfpm.yaml --target /app/dist --packager rpm

rpms/libfoundationdb/resources/nfpm.yaml

@@ -0,0 +1,36 @@
+# nfpm.yaml
+
+name: libfoundationdb
+version: ${PACKAGE_VERSION}
+release: ${PACKAGE_RELEASE}
+arch: amd64
+platform: linux
+section: default
+priority: extra
+description: "FoundationDB client library - Shared library for FoundationDB applications"
+
+maintainer: FoundationDB Community
+homepage: https://github.com/apple/foundationdb
+license: Apache-2.0
+
+disable_globbing: false
+
+replaces:
+  - libfoundationdb
+
+provides:
+  - libfoundationdb
+  - libfdb_c.so()(64bit)
+
+# Files to include in the package
+contents:
+  - src: /app/libfdb_c.so
+    dst: /usr/lib64/libfdb_c.so
+    file_info:
+      mode: 0755
+      owner: root
+      group: root
+
+# Scripts to run during installation/removal
+scripts:
+  postinstall: /app/resources/scripts/postinstall.sh

rpms/libfoundationdb/resources/scripts/postinstall.sh

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+
+# Update the dynamic linker cache to include the new library
+ldconfig