fix(config): point GitHub PR search tool at current repository (#16441)

.opencode/tool/github-pr-search.txt

@@ -1,6 +1,6 @@
 Use this tool to search GitHub pull requests by title and description.
 
-This tool searches PRs in the sst/opencode repository and returns LLM-friendly results including:
+This tool searches PRs in the anomalyco/opencode repository and returns LLM-friendly results including:
 - PR number and title
 - Author
 - State (open/closed/merged)