Add delete and remove operations for entry management

README.md

@@ -43,6 +43,9 @@ engine.init("tenant_1")
 engine.save("tenant_1", "user_1", "config", {"theme": "dark", "lang": "en"})
 data = engine.load("tenant_1", "config")
 print(data)  # {"theme": "dark", "lang": "en"}
+
+# Delete an entry
+engine.delete("tenant_1", "user_1", "config")
 ```
 
 ## Core Concepts
@@ -135,6 +138,32 @@ if engine.exists("tenant_1", "config"):
     print("Entry exists")
 ```
 
+### Deletion Operations
+
+```python
+# Delete an entire entry (removes from head, keeps history)
+deleted = engine.delete("tenant_1", "user_1", "config")
+# Returns True if entry existed, False otherwise
+
+# Historical snapshots remain accessible by digest
+old_config = engine.load("tenant_1", "config", digest=history[0])
+
+# Remove a specific key from an entry (Pattern 2)
+engine.put("tenant_1", "user_1", "users", "alice", {"name": "Alice", "role": "admin"})
+engine.put("tenant_1", "user_1", "users", "bob", {"name": "Bob", "role": "user"})
+
+removed = engine.remove("tenant_1", "user_1", "users", "alice")
+# Returns True if key existed, False otherwise
+
+# Entry still exists, only "alice" was removed
+all_users = engine.get("tenant_1", "users")  # Returns only bob
+```
+
+**Key differences:**
+- `delete()`: Removes entire entry from `head` file (works with both Pattern 1 and Pattern 2)
+- `remove()`: Removes a specific key from an entry, creates new snapshot (Pattern 2 only)
+- Both operations preserve historical snapshots in `objects/` directory
+
 ## Custom Serialization
 
 MyDbEngine supports three approaches for custom serialization:
@@ -271,6 +300,8 @@ engine.save("tenant_1", "user_1", "my_data", obj)
 | `put(tenant_id, user_id, entry, key, value) -> bool` | Add/update single record |
 | `put_many(tenant_id, user_id, entry, items) -> bool` | Add/update multiple records |
 | `get(tenant_id, entry, key=None, digest=None) -> object` | Get record(s) |
+| `delete(tenant_id, user_id, entry) -> bool` | Delete entire entry from head (keeps history) |
+| `remove(tenant_id, user_id, entry, key) -> bool` | Remove specific key from entry (Pattern 2) |
 | `exists(tenant_id, entry) -> bool` | Check if entry exists |
 
 ### History
@@ -350,4 +381,5 @@ See LICENSE file for details.
 ## Version History
 * 0.1.0 - Initial release
 * 0.2.0 - Added custom reference handlers
-* 0.2.1 - A handler can only be registered once
+* 0.2.1 - A handler can only be registered once
+* 0.3.0 - Added delete() and remove()