feat: module 05 assemble

Cards become JSON data in course/cards (one file per card, validated
against card.schema.json and the catalog); the M5 references load them
via registerCards and interpret effects, replacing content closures.
Adds assemble(base, donor, half), the assemble/buffHand effects with an
injected chooser, Fleshshape as the data-only Expansion Drop, and stages
course/cards in verify-references and start-module.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

course/catalog.json

@@ -174,6 +174,34 @@
     "text": "",
     "fictional": true
   },
+  {
+    "name": "Test Sponge",
+    "kind": "card",
+    "type": "minion",
+    "cost": 1,
+    "attack": 1,
+    "health": 3,
+    "text": "",
+    "fictional": true
+  },
+  {
+    "name": "Test Chorus",
+    "kind": "card",
+    "type": "minion",
+    "cost": 1,
+    "attack": 1,
+    "health": 5,
+    "text": "Your minions trigger their Deathrattles an additional time.",
+    "fictional": true
+  },
+  {
+    "name": "Test Workshop",
+    "kind": "card",
+    "type": "spell",
+    "cost": 2,
+    "text": "Assemble a Battlecry minion. Give all minions in your hand +1/+1.",
+    "fictional": true
+  },
   {
     "name": "BABA",
     "kind": "word",