feat(v4.0): Library tabs + Sidebar OAuth badge + Sharing routes

app/routers/library.py: /api/library/recents|favorites|shared|published|private|workspace
app/routers/sharing.py: /api/pages/{id}/share|publish + page_shares
app/templates/base.html: OAuth badge 🦎/🐙, '→ Library' buttons
app/templates/library.html: page avec tabs + filtres source
app/routers/dashboard.py: auth_method + github_linked dans context
tests/test_app.py: tests library + sharing + recents

app/templates/base.html

@@ -71,6 +71,11 @@
       <div class="workspace-info">
         <div class="workspace-avatar" style="{% if avatar_url %}background-image:url('{{ avatar_url }}');background-size:cover;{% else %}background:{{ avatar_color }};{% endif %}">{% if not avatar_url %}{{ user.full_name[:1].upper() if user and user.get('full_name') else workspaceInitial }}{% endif %}</div>
         <span class="workspace-name">{{ user.full_name or user.login or workspaceName }}</span>
+        {% if auth_method != 'local' %}
+          <span class="oauth-badge" title="Connected via {{ auth_method|title }}">
+            {% if auth_method == 'gitea' %}🦎 Gitea{% elif auth_method == 'github' %}🐙 GitHub{% else %}🔑 {{ auth_method|title }}{% endif %}
+          </span>
+        {% endif %}
       </div>
       <span class="workspace-chevron" :class="{ open: workspaceMenuOpen }">▾</span>
       <button class="sidebar-collapse-inline" @click.stop="sidebarCollapsed = !sidebarCollapsed" title="Collapse sidebar">
@@ -204,6 +209,9 @@
           <span class="chevron" :class="{ open: sectionsOpen.recents }" x-text="sectionsOpen.recents ? '▼' : '▶'"></span>
           <span>Recents</span>
         </div>
+        <div class="sidebar-section-actions">
+          <a href="/library?tab=Recents" class="library-link-btn" title="View in Library" @click.stop>→ Library</a>
+        </div>
       </div>
       <div class="sidebar-section-items" x-show="sectionsOpen.recents" x-transition>
         <ul class="sidebar-items" data-section="recents">
@@ -225,7 +233,7 @@
           <span>Favorites</span>
         </div>
         <div class="sidebar-section-actions">
-          <button class="section-action-btn" title="Add" @click.stop="newPage('Favorites')">+</button>
+          <a href="/library?tab=Favorites" class="library-link-btn" title="View in Library" @click.stop>→ Library</a>
         </div>
       </div>
       <div class="sidebar-section-items" x-show="sectionsOpen.favorites" x-transition>
@@ -258,7 +266,7 @@
           <span>Shared</span>
         </div>
         <div class="sidebar-section-actions">
-          <button class="section-action-btn" title="Add" @click.stop="newPage('Shared')">+</button>
+          <a href="/library?tab=Shared" class="library-link-btn" title="View in Library" @click.stop>→ Library</a>
         </div>
       </div>
       <div class="sidebar-section-items" x-show="sectionsOpen.shared" x-transition>
@@ -274,6 +282,7 @@
     </div>
 
     <!-- Private -->
+    {% if auth_method != 'local' or '/' in workspace_key %}
     <div class="sidebar-section">
       <div class="sidebar-section-header" @click="toggleSection('private')">
         <div class="sidebar-section-title">
@@ -281,9 +290,7 @@
           <span>Private</span>
         </div>
         <div class="sidebar-section-actions">
-          <button class="section-action-btn" title="View" @click.stop="">⊞</button>
-          <button class="section-action-btn" title="More" @click.stop="">⋯</button>
-          <button class="section-action-btn" title="Add page" @click.stop="newPage('Private')">+</button>
+          <a href="/library?tab=Private" class="library-link-btn" title="View in Library" @click.stop>→ Library</a>
         </div>
       </div>
       <div class="sidebar-section-items" x-show="sectionsOpen.private" x-transition>
@@ -297,6 +304,7 @@
         </ul>
       </div>
     </div>
+    {% endif %}
 
     <!-- Notion apps / Utilities -->
     <div class="sidebar-section">
@@ -310,7 +318,9 @@
         <ul class="sidebar-items">
           <li class="sidebar-item" @click="navigateTo('/library')"><span class="page-icon">📚</span><span class="page-name">Library</span></li>
           <li class="sidebar-item"><span class="page-icon">✅</span><span class="page-name">My Tasks</span></li>
+          {% if auth_method == 'local' or (workspace_pages and workspace_pages|length > 0) %}
           <li class="sidebar-item" @click="navigateTo('/trash')"><span class="page-icon">🗑️</span><span class="page-name">Trash</span></li>
+          {% endif %}
           <li class="sidebar-item"><span class="page-icon">❓</span><span class="page-name">Help</span></li>
         </ul>
       </div>