fix(todo): make Todo id field optional for OpenCode beta compatibility

- Make id field optional in all Todo interfaces (TodoInfo, Todo, TodoItem)
- Fix null-unsafe comparisons in todo-sync.ts to handle missing ids
- Add test case for todos without id field preservation
- All tests pass and typecheck clean

src/hooks/session-recovery/storage/message-dir.ts

@@ -1,21 +1 @@
-import { existsSync, readdirSync } from "node:fs"
-import { join } from "node:path"
-import { MESSAGE_STORAGE } from "../constants"
-
-export function getMessageDir(sessionID: string): string {
-  if (!existsSync(MESSAGE_STORAGE)) return ""
-
-  const directPath = join(MESSAGE_STORAGE, sessionID)
-  if (existsSync(directPath)) {
-    return directPath
-  }
-
-  for (const dir of readdirSync(MESSAGE_STORAGE)) {
-    const sessionPath = join(MESSAGE_STORAGE, dir, sessionID)
-    if (existsSync(sessionPath)) {
-      return sessionPath
-    }
-  }
-
-  return ""
-}
+export { getMessageDir } from "../../../shared/opencode-message-dir"