fix(shim): relicense the JSR shim package to MPL-2.0 (#299)

JSR validates the `license` field in `deno.json` against the SPDX
list and rejects unrecognised identifiers.  The repo's house licence
`PMPL-1.0-or-later` is not on the SPDX list (it's the custom Polymath
Public License), so the v0.1.2 publish failed with:

    Failed to publish @hyperpolymath/affinescript at 0.1.2:
      The license specified … was not recognized.

Relicense the shim package — and only the shim package — under
`MPL-2.0` (Mozilla Public License 2.0).  MPL-2.0 is on the SPDX list
(no `LicenseRef-` prefix needed), is OSI-approved, and is the licence
the estate has been moving toward (see memory + JULIA-SUITE notes).

Scope is deliberately narrow: 5 files inside
`packages/affinescript-cli/` (`deno.json` + the four
`SPDX-License-Identifier:` headers in `mod.js`, `mod.d.ts`,
`pins.js`, `mod_test.js`).  The rest of the repo stays on PMPL —
this PR does NOT do a repo-wide licence sweep, the code generators
that emit PMPL headers stay unchanged, and `LICENSES/` is not
modified.  A separate, deliberate decision is needed for any wider
move; flagged in the PR description.

Verification
- `deno publish --dry-run`: clean, 4 files.
- `deno test mod_test.js`: 6/6 green.
- License field value (`MPL-2.0`) recognised by SPDX/JSR.

Last blocker for the v0.1.2 JSR publish: package exists, OIDC
trusted publisher is wired, types are typed, license is now SPDX.

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

Author: hyperpolymath

packages/affinescript-cli/deno.json

@@ -4,7 +4,7 @@
   "exports": {
     ".": "./mod.js"
   },
-  "license": "PMPL-1.0-or-later",
+  "license": "MPL-2.0",
   "publish": {
     "exclude": ["mod_test.js"]
   },

packages/affinescript-cli/mod.d.ts

@@ -1,4 +1,4 @@
-// SPDX-License-Identifier: PMPL-1.0-or-later
+// SPDX-License-Identifier: MPL-2.0
 // Copyright (c) 2026 Jonathan D.A. Jewell (hyperpolymath) <j.d.a.jewell@open.ac.uk>
 //
 // Type declarations for mod.js — the @hyperpolymath/affinescript shim.

packages/affinescript-cli/mod.js

@@ -1,4 +1,4 @@
-// SPDX-License-Identifier: PMPL-1.0-or-later
+// SPDX-License-Identifier: MPL-2.0
 // Copyright (c) 2026 Jonathan D.A. Jewell (hyperpolymath) <j.d.a.jewell@open.ac.uk>
 //
 // @hyperpolymath/affinescript — the thin compiler shim (ADR-019 / #260 S3).

packages/affinescript-cli/mod_test.js

@@ -1,4 +1,4 @@
-// SPDX-License-Identifier: PMPL-1.0-or-later
+// SPDX-License-Identifier: MPL-2.0
 // Copyright (c) 2026 Jonathan D.A. Jewell (hyperpolymath) <j.d.a.jewell@open.ac.uk>
 //
 // @hyperpolymath/affinescript shim tests (ADR-019 / #260 S3).

packages/affinescript-cli/pins.js

@@ -1,4 +1,4 @@
-// SPDX-License-Identifier: PMPL-1.0-or-later
+// SPDX-License-Identifier: MPL-2.0
 // Copyright (c) 2026 Jonathan D.A. Jewell (hyperpolymath) <j.d.a.jewell@open.ac.uk>
 //
 // ADR-019 / #260: the pin table. ONE compiler version + ONE sha256 per