Initiative: Fleet-enable the idea→initiative pipeline (Option A — per-repo stub → central planner) #817

Let any petry-projects repo turn an approved Ideas Discussion into an inert initiative epic + story DAG by adding idea:approved — using a thin per-repo caller stub that dispatches the central initiative-planner in .github-private with the host repo as the target. BMAD frameworks/tooling/tests stay vendored once; the two human gates (idea:approved, then initiative:auto on the epic) stay in each repo.

Why

Today the idea:approved automation is hard-bound to .github-private: initiative-planner.yml targets REPO = github.repository, has no workflow_call, and has no standards/workflows/ caller stub. So approving an idea only works for Discussions filed in .github-private. This initiative mirrors the proven dev-lead distribution model (a central reusable + thin per-repo caller stub) to make the planner serve the whole fleet, and fixes every cross-cutting blocker (cross-repo credentials, concurrency keying, the stale-base regression class from #655, project-board funnel, and a live trigger canary).

Shape (Option A)

Per-repo stub fires on discussion [labeled] idea:approved → redispatch.sh calls gh workflow run initiative-planner.yml --repo petry-projects/.github-private -f discussion=<n> -f target_repo=<host> → central plan job reads/writes the target repo via a cross-repo App token.

Non-goals

• No change to Bob's planning logic; the planner is parameterized, not rewritten.
• No per-repo vendoring of frameworks/.
• No change to the initiative:auto → initiative-driver → dev-lead half of the pipeline.

Implementation note (cross-repo)

The code split spans two repos: planner/tooling/tests live in petry-projects/.github-private; the caller stubs and ci-standards.md live in the public petry-projects/.github. Stories name their target repo in Dev Notes; PRs land in the repo that owns each surface.

Related

• Scoped from the investigation of the idea:approved automation (pipeline doc docs/initiatives/idea-to-initiative-pipeline.md).
• Builds on the regression analysis in bug: stale-base merge (#606) silently reverted the initiative-planner discussion→dispatch fix (#618); idea:approved stopped planning #655 (stale-base semantic revert of the discussion→dispatch bridge) and the Fleet Monitor health-check [Fleet Monitor] petry-projects/.github-private — .github/workflows/initiative-planner.yml #627.

Untracked prerequisites

• GitHub Discussions enabled with an "Ideas" category on each fleet repo to be enrolled (feature-ideation already requires this).
• Org-admin access to provision a GitHub App / org secret for cross-repo writes (S1) and to set branch protection / merge queue (S6).