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]>

docs/architecture/decisions/0051-module-package-license-material.md

@@ -1,6 +1,6 @@
 # 0051: Module packages declare their own license and carry its text
 
-- Status: Proposed
+- Status: Accepted
 - Date: 2026-10-07
 - Amends: [0049](0049-module-package-v1.md) — every Module Package v1 artifact gains an
   authoritative package-level license declaration and a `LICENSE` payload. `packageFormat` stays 1.

docs/architecture/decisions/README.md

@@ -59,4 +59,4 @@ ADRs capture durable choices that affect more than one package or phase.
 - [0048: Ekklesia ships one generic image, and installed modules live outside it](0048-generic-image-and-installed-module-storage.md) — Accepted
 - [0049: A module release is one immutable, self-contained package: Ekklesia Module Package v1](0049-module-package-v1.md) — Accepted
 - [0050: Module Database ABI v1: modules and Core exchange SQL, never ORM objects](0050-module-database-abi-v1.md) — Accepted
-- [0051: Module packages declare their own license and carry its text](0051-module-package-license-material.md) — Proposed
+- [0051: Module packages declare their own license and carry its text](0051-module-package-license-material.md) — Accepted