feat: add soft delete, restore, permanent delete, and recycle bin endpoints

- Add DELETE /api/projects/:id - Soft delete project (sets deletedAt)
- Add POST /api/projects/:id/restore - Restore from recycle bin
- Add DELETE /api/projects/:id/permanent - Permanent delete
- Add GET /api/recycle-bin - List deleted items sorted by deletedAt DESC

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

server.js

@@ -977,6 +977,137 @@ app.put('/api/projects/:id', requireAuth, (req, res) => {
   }
 });
 
+// DELETE /api/projects/:id - Soft delete project
+app.delete('/api/projects/:id', requireAuth, (req, res) => {
+  try {
+    const { id } = req.params;
+
+    // Validate ID
+    const validatedId = validateProjectId(id);
+    if (!validatedId) {
+      return res.status(400).json({ error: 'Invalid project ID' });
+    }
+
+    // Check if project exists and is not already deleted
+    const existing = db.prepare(`
+      SELECT id FROM projects
+      WHERE id = ? AND deletedAt IS NULL
+    `).get(validatedId);
+
+    if (!existing) {
+      return res.status(404).json({ error: 'Project not found' });
+    }
+
+    // Soft delete by setting deletedAt
+    const now = new Date().toISOString();
+    db.prepare(`
+      UPDATE projects
+      SET deletedAt = ?
+      WHERE id = ?
+    `).run(now, validatedId);
+
+    res.json({ success: true });
+  } catch (error) {
+    console.error('Error soft deleting project:', error);
+    res.status(500).json({ error: 'Failed to delete project' });
+  }
+});
+
+// POST /api/projects/:id/restore - Restore project from recycle bin
+app.post('/api/projects/:id/restore', requireAuth, (req, res) => {
+  try {
+    const { id } = req.params;
+
+    // Validate ID
+    const validatedId = validateProjectId(id);
+    if (!validatedId) {
+      return res.status(400).json({ error: 'Invalid project ID' });
+    }
+
+    // Check if project exists and is in recycle bin
+    const existing = db.prepare(`
+      SELECT id FROM projects
+      WHERE id = ? AND deletedAt IS NOT NULL
+    `).get(validatedId);
+
+    if (!existing) {
+      return res.status(404).json({ error: 'Project not found in recycle bin' });
+    }
+
+    // Restore by setting deletedAt to NULL
+    db.prepare(`
+      UPDATE projects
+      SET deletedAt = NULL
+      WHERE id = ?
+    `).run(validatedId);
+
+    res.json({ success: true });
+  } catch (error) {
+    console.error('Error restoring project:', error);
+    res.status(500).json({ error: 'Failed to restore project' });
+  }
+});
+
+// DELETE /api/projects/:id/permanent - Permanently delete project
+app.delete('/api/projects/:id/permanent', requireAuth, (req, res) => {
+  try {
+    const { id } = req.params;
+
+    // Validate ID
+    const validatedId = validateProjectId(id);
+    if (!validatedId) {
+      return res.status(400).json({ error: 'Invalid project ID' });
+    }
+
+    // Check if project exists
+    const existing = db.prepare(`
+      SELECT id FROM projects
+      WHERE id = ?
+    `).get(validatedId);
+
+    if (!existing) {
+      return res.status(404).json({ error: 'Project not found' });
+    }
+
+    // Permanently delete the project
+    db.prepare(`
+      DELETE FROM projects
+      WHERE id = ?
+    `).run(validatedId);
+
+    res.json({ success: true });
+  } catch (error) {
+    console.error('Error permanently deleting project:', error);
+    res.status(500).json({ error: 'Failed to permanently delete project' });
+  }
+});
+
+// GET /api/recycle-bin - List deleted items
+app.get('/api/recycle-bin', requireAuth, (req, res) => {
+  try {
+    const items = db.prepare(`
+      SELECT id, name, description, icon, path, deletedAt
+      FROM projects
+      WHERE deletedAt IS NOT NULL
+      ORDER BY deletedAt DESC
+    `).all();
+
+    // Add sessionCount (0 for now, will be implemented in Task 4)
+    const itemsWithSessionCount = items.map(item => ({
+      ...item,
+      sessionCount: 0
+    }));
+
+    res.json({
+      success: true,
+      items: itemsWithSessionCount
+    });
+  } catch (error) {
+    console.error('Error listing recycle bin:', error);
+    res.status(500).json({ error: 'Failed to list recycle bin' });
+  }
+});
+
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