Mention in docs that --allow-run=bash is required for tests

The new chpwd-hook integration test spawns a bash subprocess to drive
the generated shellcode end-to-end. AGENTS.md's documented test
command needs the matching permission flag. Scoped to bash so the test
suite cannot spawn arbitrary executables.

Author: gaggle

AGENTS.md

@@ -7,7 +7,7 @@ Public repository for developer environment activation tooling.
 - `deno fmt --check .`
 - `deno lint .`
 - `deno check ./app.ts`
-- `deno test --allow-read --allow-write --allow-env`
+- `deno test --allow-read --allow-write --allow-env --allow-run=bash`
 
 ## Always Do