feat(conformance): wire cross-feature reader pattern into docs and schema

Add reads field to UseCaseManifest, update CLAUDE.md with Q0-Q3 rules,
add ./reader subpath to AGENTS.md exports table, and cascade reader
conventions through conformance quickref, adding-a-feature guide, and
scaffolding guide. Moves gen reader from deferred to planned.

docs/guides/adding-a-feature.md

@@ -29,7 +29,7 @@ per-use-case patterns below.
 
 For any new use case, follow these four steps in order:
 
-1. **Manifest entry** — declare the use case in `src/feature.manifest.ts` with its `mutates` flag and (initially empty) `audits` / `publishes` / `consumes` arrays.
+1. **Manifest entry** — declare the use case in `src/feature.manifest.ts` with its `mutates` flag and (initially empty) `audits` / `publishes` / `consumes` / `reads` arrays.
 2. **Contracts** — export `xInputSchema`, `xOutputSchema`, and the `IXUseCase` type alias from the use-case file. Factory body starts as `throw new Error("not implemented")`.
 3. **Tests (red)** — write the failing test that exercises the contract via the factory + a mock repository.
 4. **Implementation (green)** — fill the factory body until the tests pass.
@@ -55,6 +55,7 @@ Every feature package owns:
 | `di/`                             | `symbols.ts` + `module.ts` + `container.ts` + `bind-production.ts`                           |
 | `integrations/api/`               | `procedures.ts` (feature error map) + `router.ts` (uses `xProcedure.input(xInputSchema)`)    |
 | `integrations/cms/`               | Payload collection/global configs                                                            |
+| `integrations/readers/`           | `I<Feature>Reader` interface + implementation (when feature exposes cross-feature queries)   |
 | `ui/`                             | Query builders and future React components (behind `./ui` subpath)                           |
 | `__factories__/`                  | Test data factories                                                                          |
 | `__contracts__/`                  | Contract suites shared by mock and real repository tests                                     |

docs/guides/conformance-quickref.md

@@ -21,6 +21,7 @@ export const fooManifest = defineFeature({
       audits: ["thing.created"],
       publishes: ["foo.thing-created"],
       consumes: [],
+      reads: ["auth"], // cross-feature reader dependency
     },
   },
   realtimeChannels: [],
@@ -40,6 +41,7 @@ Field reference:
 | `useCases.<name>.audits`    | string[]          | Audit event types this use case emits via `auditLog.record({ type: "X" })`                                        |
 | `useCases.<name>.publishes` | string[]          | Cross-feature events this use case publishes via `bus.publish("X")`                                               |
 | `useCases.<name>.consumes`  | string[]          | Cross-feature events this use case consumes (via an event handler)                                                |
+| `useCases.<name>.reads`     | string[]          | Other features whose readers this use case queries (e.g. `["auth"]`)                                              |
 | `realtimeChannels`          | string[]          | Realtime channels this feature owns                                                                               |
 | `jobs`                      | string[]          | Job slugs this feature enqueues                                                                                   |
 | `requiresConsent`           | ConsentCategory[] | Consent categories feature use cases require; drives `withConsent` wrapping + `no-undeclared-consent-check`       |

docs/guides/scaffolding-a-feature.md

@@ -111,6 +111,7 @@ pnpm turbo gen event consume     # consumer handler + Payload event-task
 pnpm turbo gen job               # background job + TaskConfig
 pnpm turbo gen realtime channel  # realtime channel descriptor (ADR-016)
 pnpm turbo gen realtime handler  # inbound realtime handler (ADR-016)
+pnpm turbo gen reader            # cross-feature reader interface + implementation
 ```
 
 The event/job generators insert at six fixed `// <gen:*>` anchor comments. Generated features include four of them automatically (the `// <gen:job-tasks>` location is in `integrations/cms/index.ts`, which is manually authored as part of the post-scaffold wiring); pre-existing features were retrofitted in ADR-015.
@@ -127,4 +128,5 @@ The realtime generators insert at three additional fixed `// <gen:realtime-*>` a
 - `docs/decisions/adr-013-input-output-unification.md` — schemas-in-use-case + presenter
 - `docs/decisions/adr-014-instrumentation-sentry.md` — span + capture wiring
 - `docs/decisions/adr-015-events-and-jobs.md` — cross-feature events + background jobs
+- `docs/decisions/adr-026-cross-feature-readers.md` — cross-feature synchronous readers
 - `docs/decisions/adr-016-realtime-layer.md` — Socket.IO realtime channels + handlers