ci: switch pipelines to pre-baked ci-base image (consumer) [Phase 1b]

Consumer half of the Woodpecker CI cache work (#634). Re-scoped from the
original combined change: the image recipe (Dockerfile.ci, ci-image.yml)
now lives in the producer PR #637. This branch only flips the consumers.

- ci.yml / publish.yml: pull git.mosaicstack.dev/mosaicstack/stack/ci-base
  :latest for the install step and resolve from the baked pnpm store via
  --prefer-offline (drops the per-run apk add + cold network fetch).
- framework monorepo template: single cached install instead of npm ci per
  step, so scaffolded repos inherit the fix.

B2 fix (blocker): pin store-dir in root .npmrc to
/root/.local/share/pnpm/store — the exact path Dockerfile.ci warms — so the
pipeline install actually consumes the baked store instead of repopulating
a fresh one. The existing @mosaicstack registry line is preserved.

BLOCKED ON: PR #637 merge + a manual ci-image prime of ci-base:latest on
main. Until the image is primed this branch's CI is red (it pulls an image
that does not exist yet). Do not merge until a green re-run after priming.

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

packages/mosaic/framework/tools/quality/templates/monorepo/.woodpecker.yml

@@ -2,12 +2,20 @@
 when:
   - event: [push, pull_request, manual]
 
+# Dependencies are installed ONCE in the `install` step and every downstream
+# step depends on it, reusing the populated node_modules from the shared
+# workspace volume. Do NOT re-run `npm ci` per step — that pays the full cold
+# install (network fetch + native rebuilds) N times and is the dominant cost
+# in a pipeline.
+#
+# For best results, replace `&node_image` with a pre-baked CI base image that
+# ships your toolchain (python3/make/g++ for native modules) and a warm npm
+# cache, then keep `--prefer-offline` so installs resolve from the cache. See
+# the Mosaic Stack repo's Dockerfile.ci + .woodpecker/ci-image.yml for the
+# baked-image pattern.
 variables:
   - &node_image 'node:20-alpine'
   - &gitleaks_image 'ghcr.io/gitleaks/gitleaks:v8.24.0'
-  - &install_deps |
-    corepack enable
-    npm ci --ignore-scripts
 
 steps:
   # Secret scanning (runs in parallel with install, no deps)
@@ -17,15 +25,18 @@ steps:
       - gitleaks git --redact --verbose --log-opts="HEAD~1..HEAD"
     depends_on: []
 
+  # Single cached install. Every other step depends on this and reuses the
+  # node_modules it produces in the shared workspace.
   install:
     image: *node_image
     commands:
-      - *install_deps
+      - corepack enable
+      - npm ci --ignore-scripts --prefer-offline
+    depends_on: []
 
   security-audit:
     image: *node_image
     commands:
-      - *install_deps
       - npm audit --audit-level=high
     depends_on:
       - install
@@ -35,7 +46,6 @@ steps:
     environment:
       SKIP_ENV_VALIDATION: 'true'
     commands:
-      - *install_deps
       - npm run lint
     depends_on:
       - install
@@ -45,7 +55,6 @@ steps:
     environment:
       SKIP_ENV_VALIDATION: 'true'
     commands:
-      - *install_deps
       - npm run type-check
     depends_on:
       - install
@@ -55,7 +64,6 @@ steps:
     environment:
       SKIP_ENV_VALIDATION: 'true'
     commands:
-      - *install_deps
       - npm run test -- --coverage --coverageThreshold='{"global":{"branches":80,"functions":80,"lines":80,"statements":80}}'
     depends_on:
       - install
@@ -66,7 +74,6 @@ steps:
       SKIP_ENV_VALIDATION: 'true'
       NODE_ENV: 'production'
     commands:
-      - *install_deps
       - npm run build
     depends_on:
       - lint