Refactor: remove desktop/Tauri bundle, add i18n, CI/CD pipeline

- Remove desktop (Tauri) bundle: docs/desktop.md, icons/, tauri.conf.json,
  src/desktop/mod.rs, gen/schemas/
- Remove build.rs (no longer needed)
- Add i18n system (crates/core-api, plugin-mobile-connector, web)
- Refactor config system (src/config.rs, boot_format.rs)
- Add mobile connector features (app, router, device pairing)
- Plugin system improvements (skald-core)
- Update dependencies (Cargo.lock, Cargo.toml)
- CI/CD: Gitea Actions workflows (nightly + release), package.sh,
  verify-version.sh, builds.skaldagent.net config

web/lib/chat-session.js

@@ -1,3 +1,4 @@
+import { html, nothing } from 'lit';
 import { LightElement } from './base.js';
 import { t } from './i18n.js';
 
@@ -29,6 +30,7 @@ export class ChatSession extends LightElement {
     _expanded:           { state: true },
     _providers:          { state: true },
     _selectedClient:     { state: true },
+    _providersLoaded:    { state: true },
     _rejectingId:           { state: true },
     _rejectNote:            { state: true },
     _clarificationAnswer:   { state: true },
@@ -54,6 +56,7 @@ export class ChatSession extends LightElement {
     this._ws                = null;
     this._providers         = [];
     this._selectedClient    = null;
+    this._providersLoaded   = false;
     this._rejectingId           = null;
     this._rejectNote            = '';
     this._clarificationAnswer   = '';
@@ -116,9 +119,30 @@ export class ChatSession extends LightElement {
       this._selectedClient = def;
     } catch (e) {
       console.error('Failed to load LLM models:', e);
+    } finally {
+      this._providersLoaded = true;
     }
   }
 
+  get _noModels() {
+    return this._providersLoaded
+      && this._providers.filter(p => p !== 'auto').length === 0;
+  }
+
+  _renderNoModelsBanner() {
+    if (!this._noModels) return nothing;
+    return html`
+      <div class="home-banner home-banner--error chat-no-models">
+        <div class="home-banner-icon"><i class="bi bi-cpu-fill"></i></div>
+        <div class="home-banner-body">
+          <strong>${t('dashboard.banner.no_models.title')}</strong>
+          ${t('dashboard.banner.no_models.desc')}
+          <a href="#llm-providers">${t('dashboard.banner.no_models.action')}</a>
+        </div>
+      </div>
+    `;
+  }
+
   async _loadHistory() {
     try {
       const res = await fetch(`/api/${this._source}/messages`);