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>

TODO.md

@@ -12,10 +12,16 @@ The structure organizes **future tasks** by their impact, just as a changelog or
 
 Tasks in workplan: `workplans/kaizen-agentic-WP-0006-scheduled-agent-execution.md` (v1.3.0)
 
-### To Add
+### Implemented (pending v1.3.0 tag)
 * **ADR-005 + `.kaizen/schedule.yml`** — scheduled agent execution contract
 * **`kaizen-agentic schedule`** — validate, init, prepare, list
 * **activity-core definitions** — weekly coach + optimization on preselected repos
+* **Resolver + roster + event design** — `discover_kaizen_scheduled_repos`,
+  State Hub roster fields, `kaizen.schedule.prepared` payload, handoff checklist
+
+### To Add (release)
+* **Tag v1.3.0** — once activity-core handoff issue is opened and pilot smoke-tested
+* **activity-core implementation** — resolver + sync (separate repo; see handoff doc)
 
 ### Deferred to WP-0007 (v1.3.0+)
 * Interactive agent selection wizard