Add close button functionality to project tabs in Claude IDE

Fix missing 'x' close buttons on project tabs (Level 1). Session tabs
( Level 2) already had close buttons implemented.

Changes:
- project-manager.js: Added close button element to renderProjectTab()
- Added closeProject() method with confirmation dialog
- Added getSessionName() helper for session name display
- Auto-switches to next project when active project is closed
- project-tabs.css: Added .tab-close styling for project tabs
- Close button shows on hover, red highlight on hover
- Mobile responsive: always visible on small screens

The close button removes project tab from view but sessions remain
accessible via API/reload. Confirmation shows session count and list
for non-empty projects.

Resolves: https://rommark.dev/claude/ide/session/session-1769083280612-mdof554ot

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

public/claude-ide/project-manager.js

@@ -189,6 +189,7 @@ class ProjectManager {
                 <span class="tab-icon">📁</span>
                 <span class="tab-label">${escapeHtml(project.name)}</span>
                 ${sessionCount > 0 ? `<span class="tab-count">${sessionCount}</span>` : ''}
+                <span class="tab-close" onclick="event.stopPropagation(); window.projectManager.closeProject('${project.id}')">×</span>
             </button>
         `;
     }
@@ -411,6 +412,84 @@ class ProjectManager {
         }
     }
 
+    /**
+     * Close a project (with confirmation)
+     */
+    async closeProject(projectId) {
+        const projectKey = projectId.replace('project-', '');
+        const project = this.projects.get(projectKey);
+        if (!project) return;
+
+        // Check if project has sessions
+        if (project.sessions.length > 0) {
+            const sessionList = project.sessions.map(s => this.getSessionName(s)).join(', ');
+            if (!confirm(`Close project "${project.name}"?\n\nThis project contains ${project.sessions.length} session(s):\n${sessionList}\n\nThe sessions will remain accessible but the project tab will be removed.`)) {
+                return;
+            }
+        } else {
+            if (!confirm(`Close project "${project.name}"?`)) {
+                return;
+            }
+        }
+
+        console.log('[ProjectManager] Closing project:', projectId);
+
+        // Remove project from map
+        this.projects.delete(projectKey);
+
+        // If we closed the active project, switch to another
+        if (this.activeProjectId === projectId) {
+            const remainingProjects = Array.from(this.projects.values());
+            if (remainingProjects.length > 0) {
+                // Switch to the next available project
+                await this.switchProject(remainingProjects[0].id);
+            } else {
+                // No projects left
+                this.activeProjectId = null;
+                if (window.sessionTabs) {
+                    window.sessionTabs.setSessions([]);
+                    window.sessionTabs.render();
+                }
+                // Show empty state
+                const messagesContainer = document.getElementById('chat-messages');
+                if (messagesContainer) {
+                    messagesContainer.innerHTML = `
+                        <div class="empty-project-state">
+                            <div class="empty-icon">📁</div>
+                            <h3>No Projects</h3>
+                            <p>Create a new project to get started</p>
+                            <button class="btn-primary" onclick="window.projectManager.createNewProject()">
+                                Create Project
+                            </button>
+                        </div>
+                    `;
+                }
+            }
+        }
+
+        this.renderProjectTabs();
+    }
+
+    /**
+     * Get display name for a session
+     */
+    getSessionName(session) {
+        // Try to get name from metadata
+        if (session.metadata) {
+            if (session.metadata.project) return session.metadata.project;
+            if (session.metadata.title) return session.metadata.title;
+            if (session.metadata.name) return session.metadata.name;
+        }
+
+        // Use working directory
+        if (session.workingDir) {
+            return session.workingDir.split('/').pop();
+        }
+
+        // Fallback to session ID
+        return session.id.substring(0, 8);
+    }
+
     /**
      * Refresh all projects
      */