feat(ci): baked CI image + runner config + self-check workflow (T14)

Stand up the foundation's own CI on its Forgejo runner. The committed scope here
is the self-contained half (toolchain + typecheck); the stack-state-dependent
pipelines (pulumi preview, backup-verify) need CI secrets + a state fetch and
land next.

- containers/ci-image/Dockerfile + VERSIONS IMAGE_CI: one baked image carrying
  exactly what preflight validates (pulumi/bun/node/docker/git/age/zstd/jq/vault/
  psql/mc). Built on the VM (like caddy-cloudflare) and used LOCALLY by the runner.
- runner.ts: give act_runner a config.yaml — container.network=foundation-net (so
  job containers reach foundation-forgejo:3000 for checkout + the data plane) and
  force_pull=false (use the local foundation-ci image, no registry). Self-heals on up.
- .forgejo/workflows/ci.yml: preflight (tools + versions vs VERSIONS pins) +
  typecheck (bun install + tsc --noEmit on bootstrap). Gates every push.
- run.sh / backup.sh / restore.sh / dr: take PULUMI_CONFIG_PASSPHRASE from env when
  set (CI secret), falling back to `pass` (operator) — so the scripts run pass-free
  in CI.

Reusable-workflows architecture (per the chosen direction) — the ecosystem CI
(semantic-release, docker/npm/bun builds, eslint/yamllint over the 999_testing.md
candidates) builds on this image + runner next phase.

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

.forgejo/workflows/ci.yml

@@ -0,0 +1,32 @@
+# CI — foundation self-checks (T14). Runs on the foundation's own runner, in the
+# baked foundation-ci image (VERSIONS IMAGE_CI; force_pull:false → local image).
+# These two jobs are self-contained (checkout + toolchain only) — no stack state or
+# secrets needed, so they gate every push. The stack-state-dependent pipelines
+# (pulumi preview, backup-verify) live in their own files and need CI secrets +
+# a state fetch (see those workflows' headers).
+name: CI
+on:
+  push:
+  pull_request:
+
+jobs:
+  preflight:
+    runs-on: docker
+    container:
+      image: foundation-ci:latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Toolchain preflight (tools present + >= VERSIONS pins)
+        run: ./preflight/preflight.sh tools versions
+
+  typecheck:
+    runs-on: docker
+    container:
+      image: foundation-ci:latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Install workspace deps
+        run: bun install --frozen-lockfile || bun install
+      - name: Typecheck bootstrap (tsc --noEmit)
+        working-directory: bootstrap
+        run: bunx tsc --noEmit