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

Sources/SocketControlSettings.swift

@@ -47,9 +47,9 @@ struct SocketControlSettings {
             return override
         }
 #if DEBUG
-        return "/tmp/cmuxterm-debug.sock"
+        return "/tmp/cmux-debug.sock"
 #else
-        return "/tmp/cmuxterm.sock"
+        return "/tmp/cmux.sock"
 #endif
     }