feat: heph-tui --version reports version + build SHA

heph-tui was the one daily-driver binary that did not answer --version.
Add the same clap `version = heph_core::VERSION` attribute that heph and
hephd already carry, so all three report `X.Y.Z (sha)` consistently.

Addresses the heph-tui half of the cross-binary --version task.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

crates/heph-tui/src/main.rs

@@ -21,7 +21,11 @@ enum Action {
 }
 
 #[derive(Parser)]
-#[command(name = "heph-tui", about = "Hephaestus task agenda / triage TUI")]
+#[command(
+    name = "heph-tui",
+    version = heph_core::VERSION,
+    about = "Hephaestus task agenda / triage TUI"
+)]
 struct Cli {
     /// Path to the hephd unix socket. Falls back to $HEPH_SOCKET, then the
     /// standard runtime path.

docs/changelog.d/heph-tui-version.feature.md

@@ -0,0 +1 @@
+`heph-tui --version` now reports the version plus build commit (e.g. `1.0.0 (ab6701d12)`), matching `heph` and `hephd`. All three daily-driver binaries answer `--version` consistently.