Add critical instructions and hooks for Claude Code (#8715)

Co-Authored-By: dapplion <35266934+dapplion@users.noreply.github.com>

.claude/settings.json

@@ -0,0 +1,15 @@
+{
+  "hooks": {
+    "PostToolUse": [
+      {
+        "matcher": "Edit|Write",
+        "hooks": [
+          {
+            "type": "command",
+            "command": "echo '\n[Reminder] Run: cargo fmt --all && make lint-fix'"
+          }
+        ]
+      }
+    ]
+  }
+}