fix(mesh,ui,fedimint): mesh-AI chat trigger + transport-aware reply, stop ARCHY:2 public-channel spam, AI allowlist + model dropdown, Fedimint client manifest, settings reorder, chat scroll

- mesh: stop broadcasting ARCHY:2 identity on the public channel (startup + every advert tick); receive path still parses inbound. No more public-channel spam.
- mesh assistant: trigger on !ai/!ask typed in 1:1 chat (was only the dead AssistQuery path + bare channel text); route the reply transport-aware via MeshService::send_message (Tor for federation peers, LoRa for radio) through a new AssistChatReply event consumed at the server layer — fixes replies never reaching federation askers.
- mesh assistant: per-contact !ai allowlist (allowed_contacts) bypassing trusted_only; config + RPC + is_sender_allowed.
- fedimint-clientd manifest: network_policy open -> bridge (invalid value made the loader skip the whole manifest, so fmcd never ran and federations never joined/listed).
- ui: AI panel — Claude model dropdown (Haiku/Sonnet/Opus presets) + allowlist contact picker.
- ui: Settings — App Updates + App Registry moved under Account.
- ui: mesh chat — overscroll-behavior: contain so chat scroll no longer bleeds to the contacts panel.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

neode-ui/src/views/settings/SystemSection.vue

@@ -2,8 +2,6 @@
 import InterfaceModeSection from '@/views/settings/InterfaceModeSection.vue'
 import ClaudeAuthSection from '@/views/settings/ClaudeAuthSection.vue'
 import AIDataAccessSection from '@/views/settings/AIDataAccessSection.vue'
-import SystemUpdatesSection from '@/views/settings/SystemUpdatesSection.vue'
-import AppRegistriesSection from '@/views/settings/AppRegistriesSection.vue'
 import WebhookSection from '@/views/settings/WebhookSection.vue'
 import TelemetrySection from '@/views/settings/TelemetrySection.vue'
 import BackupSection from '@/views/settings/BackupSection.vue'
@@ -14,8 +12,6 @@ import SystemDangerZone from '@/views/settings/SystemDangerZone.vue'
   <InterfaceModeSection />
   <ClaudeAuthSection />
   <AIDataAccessSection />
-  <SystemUpdatesSection />
-  <AppRegistriesSection />
   <WebhookSection />
   <TelemetrySection />
   <BackupSection />