docs(work): decompose platform-retrofit and walking-skeleton epics

platform-retrofit: 8 stories / 18 tasks (spec bundle into docs/product,
single-version release-please before deletions, demo feature removal,
web-next auth shell, optional cores, work-tree archive, library traces,
agent-doc rewrite). walking-skeleton: 11 stories / 28 tasks across
workspaces, discovery, core-runner-protocol, runner app, editor, and
the flagship connect-to-selection e2e; builds on platform-retrofit
(prose dependency note — cross-epic frontmatter unsupported).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016j8z4VHjedXDTjEDNg7qHK

docs/work/epics/walking-skeleton/08-discovery-feature/_story.md

@@ -0,0 +1,45 @@
+---
+id: 08-discovery-feature
+epic: walking-skeleton
+title: discovery feature — registry snapshots, getRegistry, scan ingestion
+type: technical-story
+status: todo
+feature: discovery
+depends-on: [07-runner-lifecycle-events-and-realtime]
+blocks: [10-web-next-wiring]
+created: 2026-07-12T10:24:14Z
+---
+
+## Goal
+
+Ship the minimal `discovery` feature: registry snapshot storage, a `getRegistry` use case, and a scan-event handler that ingests the runner's scan results — so the editor has one real component (name + props) to render (skeleton bar; full `ComponentMeta` fidelity comes with `discovery-and-library`).
+
+## Why
+
+Discovery is its own vertical — the registry outlives any single runner session, and later PRDs (`discovery-and-library`) grow it heavily. Ingestion arrives as a cross-feature reaction to the scan event `workspaces` publishes (rule E0); the handler stays private (rule E1) while `getRegistry` is the public read surface the editor route consumes.
+
+## Done when
+
+- `pnpm turbo gen feature discovery` scaffold is green.
+- Registry snapshot storage + `getRegistry` use case land manifest-first (contracts, unit tests with direct mock injection, DI wiring, tRPC procedure); the registry exposes one component with name + props from the fixture scan.
+- The scan-event handler (`events/handlers/`, never re-exported) ingests scan results into a registry snapshot; `consumes` is declared in `feature.manifest.ts`.
+- `pnpm conformance` cross-feature event closure passes — no orphan consumer.
+- Coverage bands: template defaults (PRD Implementation decisions).
+- Boot assertion green in dev-seed mode.
+- `pnpm typecheck && pnpm lint && pnpm test && pnpm conformance && pnpm fallow:audit && pnpm coverage:diff` all pass after each task.
+
+## In scope
+
+- Feature scaffold, registry snapshot storage, `getRegistry`, scan-event handler + manifest `consumes` declaration.
+- Dev-seed binder with a seeded registry so the editor works in dev-seed mode.
+
+## Out of scope
+
+- Full `ComponentMeta` fidelity, watch/HMR re-scan, perf-500 budgets (`discovery-and-library`).
+- Any write surface beyond event ingestion.
+
+## Tasks
+
+- [ ] Run `pnpm turbo gen feature discovery` → green feature scaffold (manifest, contracts, binders, controllers, tests, dev-seed).
+- [ ] Add registry snapshot storage + the `getRegistry` use case — manifest entry, contracts, red test → green impl, DI wiring, tRPC procedure; registry exposes one component with name + props; dev-seed provides a seeded registry.
+- [ ] Run `pnpm turbo gen event` for the scan-event handler (`events/handlers/on-workspaces-*.handler.ts`, never re-exported per rule E1): ingest scan results into a registry snapshot; manifest `consumes` declaration; `pnpm conformance` event closure green; handler test.