feat(upload): support Excel and Word file attachments — v0.50.61

Squash-merges PR #571 (rebased from contributor PR #566 by @renheqiang). Adds .xls/.xlsx/.doc/.docx to the file picker and MIME map. 1319 tests pass.

static/index.html

@@ -274,7 +274,7 @@
         <textarea id="msg" rows="1" placeholder="Message Hermes…"></textarea>
         <div class="composer-footer">
           <div class="composer-left">
-            <input type="file" id="fileInput" multiple accept="image/*,text/*,application/pdf,application/json,.md,.py,.js,.ts,.yaml,.yml,.toml,.csv,.sh,.txt,.log,.env" style="display:none">
+            <input type="file" id="fileInput" multiple accept="image/*,text/*,application/pdf,application/json,application/vnd.ms-excel,application/vnd.openxmlformats-officedocument.spreadsheetml.sheet,application/msword,application/vnd.openxmlformats-officedocument.wordprocessingml.document,.md,.py,.js,.ts,.yaml,.yml,.toml,.csv,.sh,.txt,.log,.env,.xls,.xlsx,.doc,.docx" style="display:none">
             <button class="icon-btn" id="btnAttach" title="Attach files">
               <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2"><path d="M21.44 11.05l-9.19 9.19a6 6 0 0 1-8.49-8.49l9.19-9.19a4 4 0 0 1 5.66 5.66l-9.2 9.19a2 2 0 0 1-2.83-2.83l8.49-8.48"/></svg>
             </button>
@@ -553,7 +553,7 @@
                 <div class="settings-section-title">System</div>
                 <div class="settings-section-meta">Instance version and access controls.</div>
               </div>
-              <span class="settings-version-badge">v0.50.60</span>
+              <span class="settings-version-badge">v0.50.61</span>
             </div>
             <div class="settings-field" style="border-top:1px solid var(--border);padding-top:12px;margin-top:8px">
               <label for="settingsPassword" data-i18n="settings_label_password">Access Password</label>