feat: Module Package v1 carries the module's own license (ADR 0051)

Every Module Package v1 now declares the module's license and carries its
text. packageFormat stays 1; pre-ADR-0051 metadata fails closed.

- Contracts: ekklesia.package.json requires an SPDX `license` expression,
  validated with spdx-expression-parse, with UNLICENSED and non-expressions
  refused. The `files` list must hold exactly one non-empty root LICENSE.
  The package contracts move to the @ekklesia/contracts/module-package
  subpath, so the SPDX parser and its data (spdx-exceptions and
  spdx-license-ids ship no licence files) never reach a module bundle
  through the SDK's re-export of the contracts root.
- Packager: reads the source package.json's string SPDX declaration and
  never invents one. It requires an explicit --license-file (a non-empty
  regular file, no symlink, no parent search, no download) and copies its
  bytes unchanged to LICENSE, listed with size and SHA-256 and covered by
  the archive digest. THIRD_PARTY_NOTICES stays third-party only, and
  bundled Ekklesia code stays in `incorporates`.
- Verifier: rejects missing or invalid license metadata, and a missing,
  unlisted, duplicated, or corrupted LICENSE, through the schema and the
  existing strict inventory.
- Template: packaged as AGPL-3.0-or-later with the repository's canonical
  LICENSE, passed explicitly (Dockerfile, smoke, docs). Packing it twice
  gives byte-identical archives.

Started by Codex; reviewed and completed in Claude Code (empty license-text
refusal, schema non-empty LICENSE, symlink and empty-file tests).

ADR 0051 is Accepted.

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

templates/module/README.md

@@ -65,6 +65,7 @@ bundles the backend into one deterministic Ekklesia Module Package (ADR 0049):
 
 ```bash
 pnpm modules:pack --module templates/module --target any --out <directory> \
+  --license-file LICENSE \
   --source-revision "$(git rev-parse HEAD)"
 ```
 
@@ -89,4 +90,9 @@ classification or approval.
 The template's `package.json` declares `"license": "AGPL-3.0-or-later"`, the license of Ekklesia
 and of official Ekklesia modules (see the repository [README](../../README.md#license) and
 [LICENSE](../../LICENSE)). A module started from the template begins with that declaration; an
-official Ekklesia module keeps it.
+official Ekklesia module keeps it. The packaging command explicitly supplies the repository's
+canonical `LICENSE`, avoiding a duplicate file in this nested template. Its exact bytes become the
+package-root `LICENSE`, while `ekklesia.package.json.license` receives the source declaration.
+Standalone modules should keep their own license file and pass its path explicitly. The packager
+does not infer or download license material, and `THIRD_PARTY_NOTICES` remains only for bundled
+third-party dependencies.