feat(release): version stamping and tag-triggered release workflow

--version/-V on the CLI, version in /api/health via Server.SetVersion,
Makefile/Dockerfile ldflags stamping from git describe, and a release
workflow on v* tags: both binaries for linux/darwin (amd64+arm64) and
windows/amd64 with SHA256SUMS attached to the Gitea release
(idempotent — reuses an existing hand-written release and skips
already-uploaded assets), plus version-tagged Docker images.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

internal/config/config.go

@@ -167,6 +167,9 @@ func PrintUsage() {
 			{"--show-results", "Show the results (default true)"},
 			{"--show-summary-results", "Show the summary results (default true)"},
 		}},
+		{"General Options", [][2]string{
+			{"--version, -V", "Print version and exit"},
+		}},
 	}
 
 	for _, group := range flagGroups {