bypass-mode perms + deny list, drop allow-list plumbing

claude-settings.json now sets permissions.defaultMode=bypassPermissions
with a small deny list (WebFetch, WebSearch, Task, TodoWrite). The
per-flavor allow list and --tools / --allowedTools CLI flags are gone
— anything not denied auto-approves. mcp.rs loses ALLOWED_BUILTIN_TOOLS,
builtin_tools_arg, allow_list, allowed_mcp_tools. The extraMcpServers
allowedTools field is parsed for back-compat but no longer wired
anywhere; restrict via permissions.deny instead.

hive-ag3nt/prompts/claude-settings.json

@@ -1,5 +1,9 @@
 {
   "autoCompactEnabled": false,
   "autoMemoryEnabled": false,
-  "effortLevel": "medium"
+  "effortLevel": "medium",
+  "permissions": {
+    "defaultMode": "bypassPermissions",
+    "deny": ["WebFetch", "WebSearch", "Task", "TodoWrite"]
+  }
 }