feat: add build version with timestamp

- Add build.rs to generate BUILD_VERSION at compile time
- Update CLI to show full version: '0.1.0 (build: 2026-03-31 11:21:37)'
- Update health endpoints to return build version
- Add chrono as build dependency

src/main.rs

@@ -625,6 +625,7 @@ async fn process_caption_module(
 #[derive(Parser)]
 #[command(name = "momentry")]
 #[command(about = "Digital asset management system with video analysis and RAG")]
+#[command(version = env!("BUILD_VERSION"))]
 struct Cli {
     #[command(subcommand)]
     command: Commands,