chore: clean up unused code and fix test imports

- Remove unused config in commands.ts
- Remove deprecated formatDepositResult function in deposit-tool.ts
- Remove unused type imports in deposit-tool.ts
- Fix import path in deposit-agent.test.ts (src/deposit-agent → src/agents/deposit-agent)

This is a cleanup commit following the agent pattern unification work.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/commands.ts

@@ -8,10 +8,6 @@ export async function handleCommand(
   command: string,
   _args: string
 ): Promise<string> {
-  const config = {
-    threshold: parseInt(env.SUMMARY_THRESHOLD || '20', 10),
-    maxSummaries: parseInt(env.MAX_SUMMARIES_PER_USER || '3', 10),
-  };
 
   switch (command) {
     case '/start':