feat(atlas): per-job CI status + build-injected version in the UI

Phase C: the CI stage now shows the latest run's per-JOB status (Lint/Test,
Build, Deploy, …), each coloured by outcome, from the Gitea /actions/tasks
per-job entries — replacing the static cd.yml job-id list when live.
LatestRunJobs/RunNodes + RunSummary.State aggregate, all test-first.

Version: injected at build via -ldflags from `git describe --tags` (CI checkout
now fetch-depth:0 + --build-arg), served in /api/atlas.json, shown in the header.
No more hand-maintained version label drifting from the git tag.

Verified: build/vet/lint(0)/test green; version ldflag served correctly.

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

internal/version/version.go

@@ -0,0 +1,6 @@
+// Package version holds the build version, injected at build time via
+// -ldflags "-X .../internal/version.Value=$(git describe --tags --always)".
+package version
+
+// Value is the build version. Defaults to "dev" for local/un-injected builds.
+var Value = "dev"