add allowedBashPatterns NixOS option for finer-grained Bash tool approval

docs/turn-loop.md

@@ -276,11 +276,21 @@ status hint moved to the wake prompt + UI header.
 
 ### Tool whitelist (`mcp::ALLOWED_BUILTIN_TOOLS`)
 
-- Allowed built-ins: `Bash`, `Edit`, `Glob`, `Grep`, `Read`,
-  `TodoWrite`, `Write`.
+- Allowed built-ins: `Bash`, `Edit`, `Glob`, `Grep`, `Read`, `Write`.
 - Denied by omission: `WebFetch`, `WebSearch`, `Task`,
-  `NotebookEdit`.
+  `NotebookEdit`, `TodoWrite`.
 - Allowed MCP tools: as listed above per flavor.
 
-`Bash` is on the allow-list pending a finer-grained pattern allow-list
-(`Bash(git *)`-style) — see [issue #21](http://localhost:3000/hyperhive/hyperhive/issues/21).
+By default `Bash` is approved wholesale — any shell command runs
+without confirmation. To restrict an agent to specific command
+families, set `hyperhive.allowedBashPatterns` in its `agent.nix`:
+
+```nix
+hyperhive.allowedBashPatterns = [ "git *" "ls *" ];
+```
+
+The harness reads `/etc/hyperhive/bash-allow.json` and replaces
+`Bash` in `--allowedTools` with `Bash(git *)` + `Bash(ls *)` etc.
+Commands outside the pattern list require confirmation — which in
+`--print` mode means they will not run. An empty list (default) keeps
+the current wholesale `Bash` entry.