Add build version metadata, changelog, and version display

Embed git commit hash, dirty flag, and target triple in all binaries
via a zero-dependency build.rs. Wire clap short/long version output
so -V shows "0.1.0 (rev abc1234)" and --version adds the target
triple. Log version at daemon startup.

Add version field to show_status control socket API response. Show
the daemon's version in fipstop's tab bar title and Runtime section.

Add CHANGELOG.md in Keep a Changelog format with the 0.1.0-alpha
release (2026-02-24) and unreleased work since then.

src/control/queries.rs

@@ -40,6 +40,7 @@ pub fn show_status(node: &Node) -> Value {
     let fwd = node.stats().snapshot().forwarding;
 
     json!({
+        "version": crate::version::short_version(),
         "npub": node.npub(),
         "node_addr": hex::encode(node.node_addr().as_bytes()),
         "ipv6_addr": format!("{}", node.identity().address()),