Convert im_webapp from static mock prototypes to real backend integration

Implements all 11 product chapters (auth, messaging, contacts, groups,
files/favorites, calls, workplace/reports, settings, security) against the
real /v1/im REST API and native Tinode WS protocol, replacing the hardcoded
mock data the ba8f48ee prototype commit shipped with. Adds src/lib/im-api.js
as the REST client, plus supporting fixes across messages-view.jsx and the
attachment/upload/download pipeline (wrong SDK auth headers, group topic
naming, seq/timezone edge cases) found via live end-to-end testing against
the real backend.

Backup checkpoint before reconciling with origin/dev's parallel rewrite.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/views/sidepanel-view.jsx

@@ -134,7 +134,20 @@ class SidepanelView extends React.PureComponent {
 
     if (chapterOneViews.includes(view)) {
       return <div id="sidepanel" className="auth-onboarding-panel">
-        <AuthOnboardingView view={view} authenticated={!!this.props.myUserId} />
+        <AuthOnboardingView
+          view={view}
+          authenticated={!!this.props.myUserId}
+          login={this.props.login}
+          loginDisabled={this.props.loginDisabled}
+          persist={this.props.persist}
+          errorText={this.props.errorText}
+          errorLevel={this.props.errorLevel}
+          onLoginRequest={this.props.onLoginRequest}
+          onPersistenceChange={this.props.onPersistenceChange}
+          onCreateAccount={this.props.onCreateAccount}
+          onImRegisterRequest={this.props.onImRegisterRequest}
+          onTenantResolved={this.props.onTenantResolved}
+          onError={this.props.onError} />
       </div>;
     }
 
@@ -147,7 +160,8 @@ class SidepanelView extends React.PureComponent {
           connected={this.props.connected}
           chatList={this.props.chatList}
           myUserId={this.props.myUserId}
-          onTopicSelected={this.props.onTopicSelected} />
+          onTopicSelected={this.props.onTopicSelected}
+          onOpenScanner={this.props.onOpenScanner} />
       </div>;
     }
 
@@ -168,19 +182,22 @@ class SidepanelView extends React.PureComponent {
 
     if (CONTACT_MANAGEMENT_VIEWS.includes(view)) {
       return <div id="sidepanel" className="contact-management-panel">
-        <ContactManagementView view={view} key={view} />
+        <ContactManagementView view={view} hashParams={this.props.hashParams} myUserId={this.props.myUserId}
+          tinode={this.props.tinode} onTopicSelected={this.props.onTopicSelected} onOpenScanner={this.props.onOpenScanner} key={view} />
       </div>;
     }
 
     if (GROUP_MANAGEMENT_VIEWS.includes(view)) {
       return <div id="sidepanel" className="group-management-panel">
-        <GroupManagementView view={view} key={view} />
+        <GroupManagementView view={view} hashParams={this.props.hashParams} myUserId={this.props.myUserId}
+          tinode={this.props.tinode} onTopicSelected={this.props.onTopicSelected} key={view} />
       </div>;
     }
 
     if (CONTENT_LIBRARY_VIEWS.includes(view)) {
       return <div id="sidepanel" className="content-library-panel">
-        <ContentLibraryView view={view} key={view} />
+        <ContentLibraryView view={view} hashParams={this.props.hashParams} myUserId={this.props.myUserId}
+          tinode={this.props.tinode} onTopicSelected={this.props.onTopicSelected} chatList={this.props.chatList} key={view} />
       </div>;
     }
 
@@ -192,19 +209,23 @@ class SidepanelView extends React.PureComponent {
 
     if (WORKPLACE_COLLABORATION_VIEWS.includes(view)) {
       return <div id="sidepanel" className="workplace-collaboration-panel">
-        <WorkplaceCollaborationView view={view} key={view} />
+        <WorkplaceCollaborationView view={view} hashParams={this.props.hashParams} myUserId={this.props.myUserId}
+          tinode={this.props.tinode} onTopicSelected={this.props.onTopicSelected} key={view} />
       </div>;
     }
 
     if (PERSONAL_SETTINGS_VIEWS.includes(view)) {
       return <div id="sidepanel" className="personal-settings-panel">
-        <PersonalSettingsView view={view} key={view} />
+        <PersonalSettingsView view={view} hashParams={this.props.hashParams} myUserId={this.props.myUserId}
+          tinode={this.props.tinode} chatList={this.props.chatList}
+          onUpdatePassword={this.props.onUpdatePassword} onDeleteAccount={this.props.onDeleteAccount}
+          onLogout={this.props.onLogout} key={view} />
       </div>;
     }
 
     if (SECURITY_SUPPORT_VIEWS.includes(view)) {
       return <div id="sidepanel" className="security-support-panel">
-        <SecuritySupportView view={view} key={view} />
+        <SecuritySupportView view={view} hashParams={this.props.hashParams} tinode={this.props.tinode} key={view} />
       </div>;
     }
 
@@ -331,7 +352,7 @@ class SidepanelView extends React.PureComponent {
                 onLogout={this.props.onLogout}
                 onDeleteAccount={this.props.onDeleteAccount}
                 onShowAlert={this.props.onShowAlert}
-                onShowBlocked={() => this.props.onNavigate('block-list')}
+                onShowBlocked={this.props.onShowBlocked}
                 onToggleIncognitoMode={this.props.onToggleIncognitoMode} />
             </Suspense> :