FEAT-177: disable automatic code review triggers

- Remove pull_request and pull_request_target triggers from
  claude-code-review workflow until org secrets are configured
  for the now-public repo
- Workflow can still be run manually via workflow_dispatch

Testing: Verified workflow file is valid YAML
Risks: No automated code reviews on new PRs until re-enabled

Author: shafty023

.github/workflows/claude-code-review.yml

@@ -1,10 +1,6 @@
 name: Claude Code Review
 
 on:
-  pull_request:
-    types: [opened]
-  pull_request_target:
-    types: [opened]
   workflow_dispatch:
 
 # Cancel in-progress runs for the same PR to prevent duplicate reviews