fix(rules-injector): remove dead batch code, add .sisyphus support

- Remove non-functional batch tool handling (OpenCode has no batch tool)
- Keep working direct tool call path (read/write/edit/multiedit)
- Apply same cleanup to directory-agents-injector and directory-readme-injector
- Add .sisyphus/rules directory support

src/hooks/rules-injector/constants.ts

@@ -17,6 +17,7 @@ export const PROJECT_RULE_SUBDIRS: [string, string][] = [
   [".github", "instructions"],
   [".cursor", "rules"],
   [".claude", "rules"],
+  [".sisyphus", "rules"],
 ];
 
 export const PROJECT_RULE_FILES: string[] = [