Add DocC documentation catalog and opt-in to SPI hosting

Author: vkuttyp

.gitignore

@@ -15,3 +15,4 @@ DerivedData/
 .idea/
 *.swp
 *~
+dd/

.spi.yml

@@ -26,3 +26,4 @@ builder:
       linux_packages:
         - freetds-dev
         - pkg-config
+      documentation_targets: [SQLClientSwift]

Sources/SQLClientSwift/SQLClientSwift.docc/SQLClientSwift.md

@@ -0,0 +1,24 @@
+# ``SQLClientSwift``
+
+A modern, native Microsoft SQL Server client for iOS, macOS, and Linux — written in Swift.
+
+## Overview
+
+SQLClient-Swift provides a clean, asynchronous API for interacting with SQL Server databases. It is built on top of the open-source FreeTDS library, offering a high-performance and reliable connection layer.
+
+### Key Features
+
+- **Native Support**: Works on all Apple platforms and Linux.
+- **Modern API**: Leverages Swift's `async/await` for asynchronous operations.
+- **Type Safety**: Automatic mapping of database rows to Swift `Decodable` types.
+- **Thread Safety**: Uses Swift actors to ensure safe concurrent access to database connections.
+- **Full Encryption Support**: Supports TLS/SSL for Azure SQL and modern SQL Server instances.
+
+## Topics
+
+### Essentials
+
+- ``SQLClient``
+- ``SQLClientConnectionOptions``
+- ``SQLClientResult``
+- ``SQLRow``