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/components/copilot.js

@@ -389,6 +389,7 @@ export class AppCopilot extends I18nMixin(ChatSession) {
       </div>
 
       <div class="copilot-input-area">
+        ${this._renderNoModelsBanner()}
         <div class="copilot-composer"
              @dragover=${(e) => e.preventDefault()}
              @drop=${(e) => this._onDrop(e)}>
@@ -416,6 +417,7 @@ export class AppCopilot extends I18nMixin(ChatSession) {
           <textarea
             class="copilot-textarea"
             rows="1"
+            ?disabled=${this._noModels}
             placeholder=${t('chat.placeholder')}
             @keydown=${this._composerKeydown}
             @input=${(e) => { this._autoResize(e.target); this._updateCmdMenu(e.target.value); }}
@@ -469,7 +471,7 @@ export class AppCopilot extends I18nMixin(ChatSession) {
                     <i class="bi bi-stop-fill"></i>
                   </button>`
                 : nothing}
-              <button class="copilot-send-btn" @click=${() => this._send()} title=${t('chat.send')}>
+              <button class="copilot-send-btn" ?disabled=${this._noModels} @click=${() => this._send()} title=${t('chat.send')}>
                 <i class="bi bi-send-fill"></i>
               </button>
             </div>

web/components/shared/chat-page.js

@@ -139,6 +139,7 @@ export class ChatPage extends ChatSession {
         </div>
 
         <div class="chat-page-input-area">
+          ${this._renderNoModelsBanner()}
           <div class="chat-page-composer"
                @dragover=${(e) => e.preventDefault()}
                @drop=${(e) => this._onDrop(e)}>
@@ -153,6 +154,7 @@ export class ChatPage extends ChatSession {
             <textarea
               class="chat-page-textarea"
               rows="1"
+              ?disabled=${this._noModels}
               placeholder=${t('chat.mobile.placeholder')}
               @input=${(e) => this._autoResize(e.target)}
               @paste=${(e) => this._onPaste(e)}
@@ -195,6 +197,7 @@ export class ChatPage extends ChatSession {
                   : nothing}
                 <button
                   class="chat-page-send"
+                  ?disabled=${this._noModels}
                   @click=${() => this._send()}
                   title=${t('chat.send')}
                 ><i class="bi bi-send-fill"></i></button>

web/css/copilot-input.css

@@ -6,6 +6,14 @@
   flex-shrink: 0;
 }
 
+.chat-no-models {
+  margin-bottom: 0.6rem;
+  padding: 0.7rem 0.9rem;
+  font-size: 0.82rem;
+}
+.chat-no-models .home-banner-icon { font-size: 1.2rem; }
+.chat-no-models a { color: var(--bs-danger); font-weight: 600; }
+
 .copilot-composer {
   position: relative;
   display: flex;

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`);

web/lib/i18n.js

@@ -23,6 +23,22 @@ export function t(key, params) {
   return s;
 }
 
+/**
+ * Merge additional strings into the dictionaries — the registration seam for
+ * plugin page fragments, which ship their own `{ en, it, fr }` table and call
+ * this at module-load time (before their first render). Keys MUST be namespaced
+ * (`plugin.<id>.<key>`) so a plugin never clobbers a core key or another
+ * plugin's. Unknown locales are created on demand; missing keys still fall back
+ * through `t()` (locale → en → key). Merging alone does not re-render — the
+ * fragment registers before it mounts, and later `locale-changed` events drive
+ * updates as usual via `I18nMixin`.
+ */
+export function addStrings(dicts) {
+  for (const [loc, map] of Object.entries(dicts || {})) {
+    DICTS[loc] = { ...(DICTS[loc] || {}), ...map };
+  }
+}
+
 export function getLocale() { return _locale; }
 
 export function setLocale(locale, { persist = false } = {}) {