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/PACKAGE_RELEASE.md

@@ -128,3 +128,27 @@ token with `TWINE_USERNAME=__token__`):
 make release-publish
 python -m twine upload dist/*
 ```
+
+## Scheduled-run runner prerequisites (WP-0006)
+
+A runner that executes a scheduled kaizen agent task (fired by activity-core)
+needs:
+
+- **`kaizen-agentic` on PATH** — `pip install kaizen-agentic` (or `pipx install
+  kaizen-agentic`) using the Gitea PyPI extra index when installing from the
+  internal registry:
+  ```bash
+  pip install kaizen-agentic \
+    --extra-index-url https://gitea.coulomb.social/api/packages/coulomb/pypi/simple/
+  ```
+- **Repo checkout reachable** at the `host_paths[<host>]` registered in State
+  Hub, with a valid `.kaizen/schedule.yml` (`kaizen-agentic schedule validate`).
+- **No State Hub required for `prepare`** — `schedule prepare` reads local
+  `.kaizen/` state only. The hub is needed by the *resolver* (activity-core),
+  not by the prepared session.
+
+**Enabling a definition** (activity-core operator): keep the kaizen definitions
+at `enabled: false` until a manual smoke test passes (see
+[INTEGRATION_PATTERNS.md Pattern 2](INTEGRATION_PATTERNS.md) and the
+[activity-core handoff checklist](integrations/activity-core-handoff-wp0006.md)),
+then flip one definition to `enabled: true` in staging before fleet-wide enable.