fix: [nomad-step-0] S0.5 — Woodpecker CI validation for nomad/vault artifacts (#825)

Locks in static validation for every Nomad+Vault artifact before it can
merge. Four fail-closed steps in .woodpecker/nomad-validate.yml, gated
to PRs touching nomad/, lib/init/nomad/, or bin/disinto:

  1. nomad config validate nomad/server.hcl nomad/client.hcl
  2. vault operator diagnose -config=nomad/vault.hcl -skip=storage -skip=listener
  3. shellcheck --severity=warning lib/init/nomad/*.sh bin/disinto
  4. bats tests/disinto-init-nomad.bats — dispatcher smoke tests

bin/disinto picks up pre-existing SC2120 warnings on three passthrough
wrappers (generate_agent_docker, generate_caddyfile, generate_staging_index);
annotated with shellcheck disable=SC2120 so the new pipeline is clean
without narrowing the warning for future code.

Pinned image versions (hashicorp/nomad:1.9.5, hashicorp/vault:1.18.5)
match lib/init/nomad/install.sh — bump both or neither.

nomad/AGENTS.md documents the stack layout, how to add a jobspec in
Step 1, how CI validates it, and the two-place version pinning rule.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

tests/disinto-init-nomad.bats

@@ -0,0 +1,93 @@
+#!/usr/bin/env bats
+# =============================================================================
+# tests/disinto-init-nomad.bats — Regression guard for `disinto init`
+# backend dispatch (S0.5, issue #825).
+#
+# Exercises the three CLI paths the Nomad+Vault migration cares about:
+#   1. --backend=nomad  --dry-run         → cluster-up step list
+#   2. --backend=nomad --empty --dry-run  → same, with "--empty" banner
+#   3. --backend=docker --dry-run         → docker path unaffected
+#
+# A throw-away `placeholder/repo` slug satisfies the CLI's positional-arg
+# requirement (the nomad dispatcher never touches it). --dry-run on both
+# backends short-circuits before any network/filesystem mutation, so the
+# suite is hermetic — no Forgejo, no sudo, no real cluster.
+# =============================================================================
+
+setup_file() {
+  export DISINTO_ROOT
+  DISINTO_ROOT="$(cd "$(dirname "$BATS_TEST_FILENAME")/.." && pwd)"
+  export DISINTO_BIN="${DISINTO_ROOT}/bin/disinto"
+  [ -x "$DISINTO_BIN" ] || {
+    echo "disinto binary not executable: $DISINTO_BIN" >&2
+    return 1
+  }
+}
+
+# ── --backend=nomad --dry-run ────────────────────────────────────────────────
+
+@test "disinto init --backend=nomad --dry-run exits 0 and prints the step list" {
+  run "$DISINTO_BIN" init placeholder/repo --backend=nomad --dry-run
+  [ "$status" -eq 0 ]
+
+  # Dispatcher banner (cluster-up mode, no --empty).
+  [[ "$output" == *"nomad backend: default (cluster-up; jobs deferred to Step 1)"* ]]
+
+  # All nine cluster-up dry-run steps, in order.
+  [[ "$output" == *"[dry-run] Step 1/9: install nomad + vault binaries"* ]]
+  [[ "$output" == *"[dry-run] Step 2/9: write + enable nomad.service (NOT started)"* ]]
+  [[ "$output" == *"[dry-run] Step 3/9: write + enable vault.service + vault.hcl (NOT started)"* ]]
+  [[ "$output" == *"[dry-run] Step 4/9: create host-volume dirs under /srv/disinto/"* ]]
+  [[ "$output" == *"[dry-run] Step 5/9: install /etc/nomad.d/server.hcl + client.hcl from repo"* ]]
+  [[ "$output" == *"[dry-run] Step 6/9: first-run vault init + persist unseal.key + root.token"* ]]
+  [[ "$output" == *"[dry-run] Step 7/9: systemctl start vault + poll until unsealed"* ]]
+  [[ "$output" == *"[dry-run] Step 8/9: systemctl start nomad + poll until ≥1 node ready"* ]]
+  [[ "$output" == *"[dry-run] Step 9/9: write /etc/profile.d/disinto-nomad.sh"* ]]
+
+  [[ "$output" == *"Dry run complete — no changes made."* ]]
+}
+
+# ── --backend=nomad --empty --dry-run ────────────────────────────────────────
+
+@test "disinto init --backend=nomad --empty --dry-run prints the --empty banner + step list" {
+  run "$DISINTO_BIN" init placeholder/repo --backend=nomad --empty --dry-run
+  [ "$status" -eq 0 ]
+
+  # --empty changes the dispatcher banner but not the step list — Step 1
+  # of the migration will branch on $empty to gate job deployment; today
+  # both modes invoke the same cluster-up dry-run.
+  [[ "$output" == *"nomad backend: --empty (cluster-up only, no jobs)"* ]]
+  [[ "$output" == *"[dry-run] Step 1/9: install nomad + vault binaries"* ]]
+  [[ "$output" == *"Dry run complete — no changes made."* ]]
+}
+
+# ── --backend=docker (regression guard) ──────────────────────────────────────
+
+@test "disinto init --backend=docker does NOT dispatch to the nomad path" {
+  run "$DISINTO_BIN" init placeholder/repo --backend=docker --dry-run
+  [ "$status" -eq 0 ]
+
+  # Negative assertion: the nomad dispatcher banners must be absent.
+  [[ "$output" != *"nomad backend:"* ]]
+  [[ "$output" != *"[dry-run] Step 1/9: install nomad + vault binaries"* ]]
+
+  # Positive assertion: docker-path output still appears — the existing
+  # docker dry-run printed "=== disinto init ===" before listing the
+  # intended forge/compose actions.
+  [[ "$output" == *"=== disinto init ==="* ]]
+  [[ "$output" == *"── Dry-run: intended actions ────"* ]]
+}
+
+# ── Flag validation ──────────────────────────────────────────────────────────
+
+@test "--backend=bogus is rejected with a clear error" {
+  run "$DISINTO_BIN" init placeholder/repo --backend=bogus --dry-run
+  [ "$status" -ne 0 ]
+  [[ "$output" == *"invalid --backend value"* ]]
+}
+
+@test "--empty without --backend=nomad is rejected" {
+  run "$DISINTO_BIN" init placeholder/repo --backend=docker --empty --dry-run
+  [ "$status" -ne 0 ]
+  [[ "$output" == *"--empty is only valid with --backend=nomad"* ]]
+}