Add integration testing infrastructure with Podman Compose

- Add docker/podman-compose.yml for Immich server (no ML)
- Add test-data/sample-photos/ with 3 public domain images
- Add scripts/start-immich.sh for container startup + admin/API key creation
- Add scripts/seed-data.sh for uploading test photos and creating albums
- Add scripts/stop-immich.sh for cleanup with volume destruction
- Add scripts/run-example.sh wrapper (fixed env var export)
- Update examples to use IMMICH_URL and IMMICH_API_KEY env vars
- Add .github/workflows/integration-test.yml for CI
- Update assets.list() to use /search/metadata endpoint
- Update AGENTS.md with example running instructions
- Add 5 new examples: search_metadata, album_management, timeline_browsing,
  delete_assets, server_info

examples/download_asset.rs

@@ -1,15 +1,29 @@
 //! Example: Download an asset from Immich
+//!
+//! This example uses environment variables for configuration:
+//! - IMMICH_URL: The Immich server URL (defaults to http://localhost:2283)
+//! - IMMICH_API_KEY: Your API key (required)
 
 use immich_sdk::Client;
 use std::fs;
 
 #[tokio::main]
 async fn main() -> Result<(), Box<dyn std::error::Error>> {
-    // Create a client
-    let client = Client::from_url("https://immich.example.com")?.with_api_key("your-api-key");
+    // Configure the client from environment variables
+    let url = std::env::var("IMMICH_URL").unwrap_or_else(|_| "http://localhost:2283".to_string());
+    let api_key =
+        std::env::var("IMMICH_API_KEY").expect("IMMICH_API_KEY environment variable not set");
 
-    // Asset ID to download (replace with a real asset ID)
-    let asset_id = "your-asset-id-here".parse()?;
+    // Create a client
+    let client = Client::from_url(&url)?.with_api_key(api_key);
+
+    // Get first asset from the server
+    let assets = client.assets().list().execute().await?;
+    if assets.is_empty() {
+        println!("No assets found. Run upload_photos example first.");
+        return Ok(());
+    }
+    let asset_id = assets[0].id;
 
     // Download the asset
     println!("Downloading asset...");