fix(docker): include .git in build context so healthz reports real SHA

.dockerignore excluded .git/, so `git rev-parse --short HEAD` inside the
Dockerfile build silently fell back to "unknown" and /healthz reported
`version: unknown` on every deploy. Remove the .git entry; the Dockerfile
already runs git inside the build stage and Dokploy clones --depth 1.

After deploy, `curl https://projax.msbls.de/healthz | tail -1` returns
the short commit SHA matching `git rev-parse --short HEAD` on main —
deploy verification becomes a one-shot SHA match instead of inspecting
container task IDs on mlake.

.dockerignore

@@ -1,4 +1,3 @@
-.git
 .worktrees
 .m
 .claude