Release v1.23.0 (#31)

* Rename cmuxterm to cmux across entire codebase

- Rename GitHub repos: manaflow-ai/cmuxterm -> manaflow-ai/cmux,
  manaflow-ai/homebrew-cmuxterm -> manaflow-ai/homebrew-cmux
- Rename bundle IDs: com.cmuxterm.app -> com.cmux.app
- Rename CLI: CLI/cmuxterm.swift -> CLI/cmux.swift
- Rename homebrew submodule: homebrew-cmuxterm -> homebrew-cmux
- Update all socket paths: /tmp/cmuxterm*.sock -> /tmp/cmux*.sock
- Update all GitHub URLs, DMG names, Sparkle URLs
- Update all source files, scripts, tests, docs, CI workflows

* Bump version to 1.23.0

Resources/shell-integration/cmux-bash-integration.bash

@@ -1,4 +1,4 @@
-# cmuxterm shell integration for bash
+# cmux shell integration for bash
 
 _cmux_send() {
     local payload="$1"
@@ -10,7 +10,7 @@ _cmux_send() {
         # Some nc builds don't support unix sockets, but keep as a last-ditch fallback.
         #
         # Important: macOS/BSD nc will often wait for the peer to close the socket
-        # after it has finished writing. cmuxterm keeps the connection open, so
+        # after it has finished writing. cmux keeps the connection open, so
         # a plain `nc -U` can hang indefinitely and leak background processes.
         #
         # Prefer flags that guarantee we exit after sending, and fall back to a