chore: consolidate duplicate test directories (#565)

Move detector.test.ts from tests/modes/ to test/modes/ and fix TypeScript
type errors by adding missing required properties (botId, botName, allowedNonWriteUsers).
Remove empty tests/ directory structure.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-authored-by: Claude <noreply@anthropic.com>

test/modes/detector.test.ts

@@ -20,7 +20,10 @@ describe("detectMode with enhanced routing", () => {
       branchPrefix: "claude/",
       useStickyComment: false,
       useCommitSigning: false,
+      botId: "123456",
+      botName: "claude-bot",
       allowedBots: "",
+      allowedNonWriteUsers: "",
       trackProgress: false,
     },
   };