feat(explorer): ship Effort Graph visualizer with flatbread start

.agents/skills/effort-graph/setup.md

@@ -84,3 +84,18 @@ On resume, begin with `flatbread effort list --status active`, then use bounded
 effort-scoped reads. Capture mutation `generation` tokens and use
 `--strict-min-generation` for immediate read-after-write checks; never implement
 client polling loops. Semantic changes go through `flatbread effort write`.
+
+## 4. Open the explorer (optional)
+
+With a complete `effortGraphContent()` preset in config, Flatbread serves the
+content-relation explorer automatically:
+
+```bash
+flatbread start --watch --open
+```
+
+- Explorer UI: `http://localhost:5057/`
+- Apollo GraphQL sandbox: `http://localhost:5057/graphql`
+
+No separate app install is required; `@flatbread/explorer` ships with
+`flatbread`.

CONTRIBUTING.md

@@ -35,7 +35,7 @@ Optional **`pnpm play`** from the repo root is a shortcut for **`cd examples/nex
 - Build all packages: `pnpm build`
 - **Workspace libraries (watch-only):** `pnpm dev` — runs package `dev` scripts (e.g. `tsup --watch`) for `packages/*`; it does **not** start the Next.js example.
 - **Next.js example:** prefer the flow under [Recommended onboarding](#recommended-onboarding-try-flatbread-in-the-nextjs-example); or `pnpm play` as a convenience alias.
-- **Effort Graph viz (`examples/effort-viz`):** after `pnpm build`, run `pnpm play:efforts` (or `pnpm --filter effort-viz dev`) to dogfood `.flatbread-efforts` with live SSE updates — see that example's README.
+- **Effort Graph explorer:** after `pnpm build`, run `pnpm play:efforts` (`flatbread start --watch --open`). When `flatbread.config.js` uses `effortGraphContent()`, Flatbread serves `@flatbread/explorer` at `http://localhost:5057/` (Apollo sandbox at `/graphql`).
 - Check local CI parity before opening a PR: `pnpm verify`
 
 ## Working on a package

ava.config.js

@@ -13,6 +13,8 @@ export default {
     // parser/runtime guardrails.
     '!packages/codegen/src/__tests__/**',
     '!packages/utils/src/__tests__/**',
+    // Explorer SPA uses Node's built-in test runner (see package scripts).
+    '!packages/explorer/**',
   ],
   extensions: {
     js: true,