Fix: Remove range copy() and correct warn() cost

Update agent list to include Codex

Co-Authored-By: Codex <codex@openai.com>

Author: heikkitoivonen

docs/builtins/range.md

@@ -15,7 +15,6 @@ The `range` type is an immutable sequence of numbers used for iteration. It gene
 | `index(value)` | O(1) | Solve equation |
 | `count(value)` | O(1) | Single check |
 | `iteration` | O(n) | n = number of items |
-| `copy()` | O(1) | Shallow copy |
 | `reversed()` | O(1) | Iterator, not materialized |
 | `list(range(...))` | O(n) | Convert to list |
 

docs/index.md

@@ -49,7 +49,7 @@ See [Built-in Types](builtins/list.md) for detailed analysis.
 
 ## Why Trust This Documentation?
 
-This documentation has been reviewed and refined through **100+ commits** by multiple AI coding agents (Amp, Claude, Antigravity, Kiro, Copilot) working alongside human contributors. Each agent brings different perspectives and catches different issues, resulting in thorough cross-validation.
+This documentation has been reviewed and refined through **100+ commits** by multiple AI coding agents (Amp, Claude, Antigravity, Kiro, Copilot, Codex) working alongside human contributors. Each agent brings different perspectives and catches different issues, resulting in thorough cross-validation.
 
 It's also **fully open source**—anyone can review the content, [file issues](https://github.com/heikkitoivonen/python-time-space-complexity/issues), or [submit improvements](https://github.com/heikkitoivonen/python-time-space-complexity/pulls). All sources are cited, and claims are based on official Python documentation and CPython source code.
 

docs/stdlib/warnings.md

@@ -17,7 +17,7 @@ The `warnings` module provides a framework for issuing and filtering warning mes
 ```python
 import warnings
 
-# Issue a warning - O(1)
+# Issue a warning - O(n) for filter scan + stack inspection
 warnings.warn("This is deprecated", DeprecationWarning)
 
 # With stack level