feat: standalone module-build readiness for the public @ekklesia packages (ADR 0053)

Makes the public module-development package set usable from a module
repository outside the monorepo. Nothing is published.

- Curated @ekklesia/module-sdk: an explicit author API, no contracts
  barrel, no identity/authorization internals, no Drizzle and no legacy
  ModuleDatabase type. defineModuleRuntime returns the SDK's own named
  interfaces so a module's emitted declarations never reach into
  @ekklesia/contracts. defineModuleSchema is gone; createModuleTable and
  defineModuleSchemaMetadata live in @ekklesia/module-database.
- Drizzle: no longer a dependency of module-sdk or contracts. Core keeps
  the legacy Drizzle schema validator (moved to core/src/modules) and
  its legacy runtime support; drizzle-orm is an optional peer only.
- React is a peer (plus devDependency) of @ekklesia/ui; the boundary
  checker allows exactly that consumer-selected peer.
- @ekklesia/typescript-config is publishable; module-ui-host is private.
  Every public package carries "ekklesia.distribution":
  "module-development" and no monorepo-root prepack.
- module-pack reads the Node.js range from the module's own engines.node
  and recognizes Ekklesia packages by name plus that marker, so
  registry-installed packages are incorporated, SDK-compatibility
  checked, and never credited as third-party.
- scripts/pack-public-packages.ts (pnpm packages:pack) rebuilds, packs
  and inspects the nine public tarballs; scripts/test-standalone-module.sh
  (pnpm test:standalone-module, new CI job) installs them into a fixture
  module outside the repository and proves it typechecks, builds,
  packages, and verifies.
- Public-package boundary tests and module-development docs.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

tests/fixtures/boundaries/legal-consumer-runtime-peer/packages/ui/package.json

@@ -0,0 +1,13 @@
+{
+  "name": "@ekklesia/ui",
+  "version": "0.0.0",
+  "type": "module",
+  "peerDependencies": { "react": "^19.2.0" },
+  "devDependencies": { "react": "19.2.8" },
+  "exports": {
+    ".": "./src/index.tsx"
+  },
+  "ekklesia": {
+    "layer": "ui"
+  }
+}

tests/fixtures/boundaries/legal-consumer-runtime-peer/packages/ui/src/index.tsx

@@ -0,0 +1,6 @@
+import { useId } from "react";
+
+export function Badge(props: { readonly label: string }) {
+  const id = useId();
+  return <span id={id}>{props.label}</span>;
+}