Close first threshold claim by default on compose screen

Drop the defaultOpen={i===0} on the first threshold_claim — when a
case has a lot of material already on screen (research background
+ chair positions + now precedents), auto-opening the first card
creates a wall of text on page load. All cards now start collapsed,
same as the issues list already did.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.taskmaster/tasks/tasks.json

@@ -903,18 +903,18 @@
         "description": "Add case_precedents table + FastAPI endpoints + MCP tools + Next.js compose UI for attaching legal precedents (quote + citation + optional archived PDF) to threshold_claims/issues and to the case as a whole. Plan: ~/.claude/plans/woolly-cooking-graham.md",
         "details": "",
         "testStrategy": "",
-        "status": "in-progress",
+        "status": "done",
         "dependencies": [],
         "priority": "high",
         "subtasks": [],
-        "updatedAt": "2026-04-11T19:13:41.219Z"
+        "updatedAt": "2026-04-11T19:20:56.040Z"
       }
     ],
     "metadata": {
       "version": "1.0.0",
-      "lastModified": "2026-04-11T19:13:41.220Z",
+      "lastModified": "2026-04-11T19:20:56.040Z",
       "taskCount": 60,
-      "completedCount": 56,
+      "completedCount": 57,
       "tags": [
         "master"
       ]