feat: scheduled agent execution via activity-core (WP-0006, v1.3.0)

Enable kaizen agents to run on a regular cadence against a preselected repo
roster, orchestrated by activity-core and prepared by kaizen-agentic — without
this repo owning cron, Temporal workers, or an LLM runtime.

CLI + module:
- src/kaizen_agentic/schedule.py — .kaizen/schedule.yml parse/validate/scaffold
- `kaizen-agentic schedule` group: init, validate, list, prepare <agent>
  (prepare bundles agent prompt + memory + metrics + repo pointers, offline)
- tests/test_schedule_cli.py — 15 tests

Contract & design:
- ADR-005 scheduled agent execution; schema doc + example manifest
- discover_kaizen_scheduled_repos resolver spec, state-hub roster fields,
  kaizen.schedule.prepared event payload, activity-core handoff checklist
- INTEGRATION_PATTERNS Pattern 2 extended with roster model

ActivityDefinition drafts (enabled: false):
- weekly-coach-orientation, weekly-optimization-review

Docs: agency-framework, CLI cheat sheet, PACKAGE_RELEASE runner prereqs,
EcosystemIntegration, CHANGELOG, TODO. Workplan closed (status: done).

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

docs/agency-framework.md

@@ -299,12 +299,35 @@ Manifest: [integrations/optimizer-artifact-manifest.md](integrations/optimizer-a
 
 ---
 
+## Scheduled Agent Execution
+
+Agents can run on a **regular cadence** against **preselected repos**, fired by
+**activity-core** and prepared by kaizen-agentic (ADR-005). A repo opts in by
+committing `.kaizen/schedule.yml`:
+
+```bash
+kaizen-agentic schedule init       # scaffold (coach + optimization weekly)
+kaizen-agentic schedule validate   # check schema + agent names
+kaizen-agentic schedule list       # show enabled entries
+kaizen-agentic schedule prepare coach   # orientation bundle for a scheduled run
+```
+
+`schedule prepare <agent>` bundles the agent prompt, project memory, metrics
+summary, and repo pointers — offline, no State Hub required. kaizen-agentic does
+**not** run cron or invoke Claude; activity-core fires the schedule and a
+coding-agent session executes the prepared bundle.
+
+Schema: [integrations/schedule-schema.md](integrations/schedule-schema.md).
+
+---
+
 ## Related Documents
 
 - [ADR-001: Workplan Convention](adr/ADR-001-workplan-convention.md)
 - [ADR-002: Project Memory Convention](adr/ADR-002-project-memory-convention.md)
 - [ADR-003: Protocols Artifact Convention](adr/ADR-003-protocols-artifact-convention.md)
 - [ADR-004: Project Metrics Convention](adr/ADR-004-project-metrics-convention.md)
+- [ADR-005: Scheduled Agent Execution](adr/ADR-005-scheduled-agent-execution.md)
 - [wiki/EcosystemIntegration.md](../wiki/EcosystemIntegration.md) — two-layer measurement model
 - [WP-0002: Agency Framework](../workplans/kaizen-agentic-WP-0002-agency-framework.md)
 - [WP-0003: Measurement Loop](../workplans/kaizen-agentic-WP-0003-measurement-loop.md)