feat(bootstrap): shared docker provider + foundation-net precursor (ADR-006)

Composition substrate for Wave 2 (T03+):
- lib/context.ts: one Docker-over-SSH provider + DeployCtx threaded to component
  factories; FOUNDATION_DOCKER_HOST override for ephemeral validation.
- lib/versions.ts: resolve pinned images from VERSIONS; FOUNDATION_ALLOW_UNPINNED
  for local validation when digests are still PIN_DIGEST.
- components/network.ts: foundation-net (CONTRACT_003 §3.1).
- index.ts: phase-orchestration entrypoint with dependsOn gates; Wave-2 slots.
- ADR-006: shared-provider + per-component-factory model (egg does not route its
  phased bootstrap through the monolithic vendored DockerDeployments).

Validated: pulumi up over Docker-over-SSH created+verified+destroyed foundation-net
on crunchy01 (x86_64); ephemeral, nothing persisted. tsc + preview clean.

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

bootstrap/package.json

@@ -7,6 +7,7 @@
     "dependencies": {
         "@olsitec/pulumi-docker": "workspace:*",
         "@olsitec/pulumi-vault": "workspace:*",
+        "@pulumi/docker": "^4.5.8",
         "@pulumi/pulumi": "^3.138.0"
     },
     "devDependencies": {