fix(builtin-tools): handle undefined message_ids in SnipTool.call()

## Bug 详情
调用 Snip 工具时，若模型通过 ExecuteExtraTool 传入空 params，
SnipTool.call() 中访问 input.message_ids.length 会抛出
`Cannot read properties of undefined (reading 'length')`。

## 根因
Snip 是延迟工具（非 CORE_TOOLS），需通过 ExecuteExtraTool 间接调用。
ExecuteExtraTool 将 params 直接透传给目标工具，不做 Zod schema 验证。
当 params 为空对象 {} 时，input.message_ids 为 undefined。

## 修复方案
在 SnipTool.call() 中使用 optional chaining 安全访问 message_ids。

## 变更要点
- packages/builtin-tools/src/tools/SnipTool/SnipTool.ts: 防御性处理空 message_ids
- src/costrict/provider/auth.ts: 删除 unreachable continue（lint 自动修复）
- src/services/rawDump/worker.ts: Math.pow → **（lint 自动修复）

## 自测
- 已人工验证

Co-Authored-By: Auto <noreply@anthropic.com>

packages/builtin-tools/src/tools/SnipTool/SnipTool.ts

@@ -82,10 +82,11 @@ Guidelines:
     // Snip implementation is handled by the query engine's projection system.
     // The tool call itself records the intent; the query engine intercepts
     // snip tool results and adjusts its message projection accordingly.
+    const count = input.message_ids?.length ?? 0
     return {
       data: {
-        snipped_count: input.message_ids.length,
-        summary: input.reason ?? `Snipped ${input.message_ids.length} messages`,
+        snipped_count: count,
+        summary: input.reason ?? `Snipped ${count} messages`,
       },
     }
   },

src/costrict/provider/auth.ts

@@ -114,7 +114,6 @@ export async function pollLoginToken(
         throw new Error('Login cancelled')
       }
       if (error.message?.includes('Login failed')) throw error
-      continue
     }
   }
 

src/services/rawDump/worker.ts

@@ -105,7 +105,7 @@ async function postJson(
   let lastError: Error | undefined
   for (let attempt = 0; attempt < 3; attempt++) {
     if (attempt > 0) {
-      const delay = 5000 * Math.pow(2, attempt - 1) // 5s, 10s
+      const delay = 5000 * 2 ** (attempt - 1) // 5s, 10s
       log.debug(`retrying ${endpoint} after ${delay}ms`, { attempt })
       await new Promise((r) => setTimeout(r, delay))
     }