fix: Downgrade edition2024 to edition2021 for Rust 1.75 compatibility

wezterm-cell and wezterm-escape-parser were using edition2024 which
requires Rust 1.82+. Downgrading to edition2021 for broader compatibility.

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

Author: mikejmorgan-ai

wezterm-cell/Cargo.toml

@@ -2,7 +2,7 @@
 authors = ["Wez Furlong"]
 name = "wezterm-cell"
 version = "0.1.0"
-edition = "2024"
+edition = "2021"
 repository = "https://github.com/cxlinux-ai/cx"
 description = "Model a Cell in a Terminal display"
 license = "MIT"

wezterm-escape-parser/Cargo.toml

@@ -2,7 +2,7 @@
 authors = ["Wez Furlong"]
 name = "wezterm-escape-parser"
 version = "0.1.0"
-edition = "2024"
+edition = "2021"
 repository = "https://github.com/cxlinux-ai/cx"
 description = "Escape Sequence Parser"
 license = "MIT"