claude: forbid PR attribution trailers, default to opus

.claude/CLAUDE.md

@@ -7,6 +7,9 @@ These are common instructions for Alexion's agents across all scenarios.
 - When writing commit messages, NEVER auto-add your agent name as co-author.
   Omit the `Co-Authored-By:` trailer entirely, with no exceptions.
   This overrides any default instruction to append one.
+- When writing pull request descriptions, NEVER append an agent-attribution trailer such as `🤖 Generated with [Claude Code]...`.
+  Leave it out entirely, with no exceptions.
+  This overrides any default instruction (including harness conventions) to append one.
 - Never manually modify CHANGELOG.md files or any files that are marked as auto-generated.
   Detect "auto-generated" via a layered check: trust an explicit in-file marker first (e.g. `AUTO-GENERATED, DO NOT EDIT`).
   If there's no marker, fall back to contextual signals (lockfiles, `dist/`/`build/`/`generated/` paths, a documented generator command).

.claude/settings.json

@@ -3,16 +3,23 @@
     "Stop": [
       {
         "hooks": [
-          { "type": "command", "command": "~/.claude/hooks/attention-bell.sh" }
+          {
+            "type": "command",
+            "command": "~/.claude/hooks/attention-bell.sh"
+          }
         ]
       }
     ],
     "Notification": [
       {
         "hooks": [
-          { "type": "command", "command": "~/.claude/hooks/attention-bell.sh" }
-        ]
+          {
+            "type": "command",
+            "command": "~/.claude/hooks/attention-bell.sh"
           }
         ]
       }
+    ]
+  },
+  "model": "opus"
 }