ci: eliminate cold pnpm install via pre-baked CI base image (Phase 1)

Every pipeline ran a cold pnpm install (network fetch + musl native
rebuilds + apk add python3 make g++), median ~731s, paid twice per push.

Phase 1 (no cluster access, repo commits only):
- Dockerfile.ci: node:22-alpine + python3/make/g++/postgresql-client +
  pnpm@10.6.2 + pnpm fetch to warm the store and compile natives once.
- .woodpecker/ci-image.yml: kaniko build/push of ci-base:latest + a
  lockfile-hash tag, triggered only when pnpm-lock.yaml or Dockerfile.ci
  change. Reuses the publish.yml kaniko/auth pattern.
- ci.yml + publish.yml: install from the baked ci-base:latest, drop the
  per-run apk add, use pnpm install --frozen-lockfile --prefer-offline.
- Framework monorepo template: single cached install other steps depend
  on instead of re-running npm ci across 6 steps.

Node 22->24 bump is a separate follow-up PR. Phase 2 (RWX Longhorn PVC)
is out of scope. Expected install ~731s -> ~30-60s.

Refs #634

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

.woodpecker/ci.yml

@@ -1,5 +1,9 @@
+# &node_image is the pre-baked CI base built by .woodpecker/ci-image.yml:
+# node:22-alpine + python3/make/g++/postgresql-client + pnpm + a warm pnpm
+# store. The install step resolves from the baked store (--prefer-offline)
+# instead of paying a ~731s cold fetch + native compile every run.
 variables:
-  - &node_image 'node:22-alpine'
+  - &node_image 'git.mosaicstack.dev/mosaicstack/stack/ci-base:latest'
   - &enable_pnpm 'corepack enable'
 
 when:
@@ -15,8 +19,9 @@ steps:
     image: *node_image
     commands:
       - corepack enable
-      - apk add --no-cache python3 make g++
-      - pnpm install --frozen-lockfile
+      # python3/make/g++ are baked into ci-base; --prefer-offline resolves from
+      # the baked pnpm store.
+      - pnpm install --frozen-lockfile --prefer-offline
 
   # Blocking gate: public framework package must contain no operator-specific
   # personal data or private $HOME defaults. Runs early (no node_modules needed).
@@ -64,8 +69,7 @@ steps:
       DATABASE_URL: postgresql://mosaic:mosaic@ci-postgres:5432/mosaic
     commands:
       - *enable_pnpm
-      # Install postgresql-client for pg_isready
-      - apk add --no-cache postgresql-client
+      # postgresql-client (pg_isready) is baked into ci-base.
       # Wait up to 60s for CI postgres to be ready; fail fast if it never comes up.
       - |
         ready=0