WP-0004: ecosystem integration complete

Add Helix Forge correlation (HELIX_SESSION_UID env, metrics correlate),
artifact-store publish (metrics publish), activity-core ActivityDefinition
references, integration patterns docs, and canon/knowledge design artifacts.

docs/integrations/activity-definitions/post-install-metrics-scaffold.md

@@ -0,0 +1,41 @@
+---
+id: kaizen-post-install-metrics-scaffold
+name: Post-Install Metrics Scaffold Validation
+enabled: false
+owner: kaizen-agentic
+governance: custodian
+status: proposed
+trigger:
+  type: event
+  event_type: kaizen.agent.installed
+context_sources:
+  - type: event-payload
+    bind_to: context.install
+---
+
+# Post-Install Metrics Scaffold Validation
+
+Fires when an agent is installed into a project. Verifies that memory and metrics
+scaffolds exist for the installed agent.
+
+```rule
+id: validate-metrics-scaffold
+condition: 'context.install.agent != ""'
+action:
+  task_template: "Validate kaizen scaffold for {{context.install.agent}}"
+  description: |
+    In {{context.install.project_root}} verify:
+    - .kaizen/agents/{{context.install.agent}}/memory.md exists OR run:
+      kaizen-agentic memory init {{context.install.agent}}
+    - .kaizen/metrics/{{context.install.agent}}/ exists OR re-run init without --no-metrics
+  target_repo: "{{context.install.repo}}"
+  priority: low
+  labels: ["kaizen", "metrics", "scaffold", "automated"]
+```
+
+**CLI mapping:**
+
+```bash
+kaizen-agentic memory init <agent>    # scaffolds memory + metrics by default
+kaizen-agentic metrics list           # confirms metrics directory after first record
+```