feat(turbo): turbo gen feature generator (Phase 1, single-entity)

Adds `pnpm turbo gen feature` to scaffold a Lazar-conformant feature
package matching the navigation reference shape: entity + Zod schema,
single use case (`get<Entity>`), controller, mock + Payload-stub real
repository (with span + capture), DI module/container/symbols, and tRPC
router with full BAD_REQUEST/NOT_FOUND error mapping. The generated
`bind-production.ts` and `bind-dev-seed.ts` compose the post-R44
`withSpan(tracer, opts, withCapture(logger, tags, factory(deps)))`
sandwich at bind time.

Verified by generating a sample `packages/example/` feature and running
`pnpm --filter @repo/example lint typecheck test` — all three pass
(9 test files, 25 tests). Cleaned up after verification so no example
package is committed.

Phase-1 limitations (documented in `docs/guides/scaffolding-a-feature.md`
and printed by the generator on success): no Payload CMS templates, no
React Query helpers, faker-driven factories left as stubs, single
entity / single use case, and aggregator wiring (core-api/root,
apps/web-next bindAll) is left as a manual checklist.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

turbo/generators/templates/feature/src/entities/models/entity.test.ts.hbs

@@ -0,0 +1,24 @@
+import { describe, expect, it } from "vitest";
+import { {{camelCase entity}}Schema } from "./{{kebabCase entity}}";
+
+describe("{{camelCase entity}}Schema", () => {
+  it("accepts a valid {{camelCase entity}}", () => {
+    const result = {{camelCase entity}}Schema.parse({ id: "1", name: "Example" });
+    expect(result.id).toBe("1");
+    expect(result.name).toBe("Example");
+  });
+
+  it("rejects an empty id", () => {
+    expect(() => {{camelCase entity}}Schema.parse({ id: "", name: "ok" })).toThrow();
+  });
+
+  it("rejects an empty name", () => {
+    expect(() => {{camelCase entity}}Schema.parse({ id: "1", name: "" })).toThrow();
+  });
+
+  it("rejects a name over 128 chars", () => {
+    expect(() =>
+      {{camelCase entity}}Schema.parse({ id: "1", name: "x".repeat(129) }),
+    ).toThrow();
+  });
+});

turbo/generators/templates/feature/src/entities/models/entity.ts.hbs

@@ -0,0 +1,8 @@
+import { z } from "zod";
+
+export const {{camelCase entity}}Schema = z.object({
+  id: z.string().min(1),
+  name: z.string().min(1).max(128),
+});
+
+export type {{pascalCase entity}} = z.infer<typeof {{camelCase entity}}Schema>;