refactor(hooks): remove grep-blocker (grep tool now overrides built-in)

The grep tool now properly overrides OpenCode's built-in grep,
making the blocker hook unnecessary.

Generated by [OpenCode](https://opencode.ai/)

src/hooks/grep-blocker.ts

@@ -1,18 +0,0 @@
-import type { PluginInput } from "@opencode-ai/plugin"
-
-const BLOCKED_MESSAGE =
-  "Error: [BLOCKED] grep has no timeout and can freeze the system. " +
-  "It is permanently disabled. Use 'safe_grep' instead."
-
-export function createGrepBlocker(_ctx: PluginInput) {
-  return {
-    "tool.execute.before": async (
-      input: { tool: string; sessionID: string; callID: string },
-      _output: { args: unknown }
-    ) => {
-      if (input.tool === "grep") {
-        throw new Error(BLOCKED_MESSAGE)
-      }
-    },
-  }
-}