Security + upstream fixes

- Network core moves to a root-only folder; BroV talks to a narrow root helper (netctl.py) over a user-only socket; install script verifies the mihomo SHA256 and migrates keys (scripts/netcore)
- Hardened runtime, no get-task-allow; bypassPermissions removed from the chat; concealed clipboard items are not restored; DangerCheck knows core, LaunchAgents and hook paths; dropped-file copies expire after 7 days
- Ported from upstream Coucou: 1h crash fix (d05f22b), safe settings.json writes (918d30e), Escape/fold for pending approvals (6012900, 40e3ba8), auto-close delay + reopen (74984f2, ea244a7), full AskUserQuestion (52b1562)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

.gitignore

@@ -10,7 +10,11 @@ DerivedData/
 # Local only
 .claude/
 
-# Secrets never live in the repo (kept in ~/Documents/brov-secrets)
+# Secrets never live in the repo (root core folder, ~/.brov-secrets)
 *.conf
 guide-*.md
 brov-secrets/
+*.vpnkey
+api.secret
+netcore.json
+config.yaml