fix: Linux process not exiting, CR-only lines overwritten in PST terminal (v0.9.23)

- Remove duplicate window-all-closed handler that raced with serial port
  cleanup, leaving /dev/ttyUSB0 held open on Linux after closing windows
- Add 5s safety timeout to shutdown so process exits even if port close hangs
- CR now implies LF in PST mode so CR-only programs display correctly;
  CR+LF programs are not double-spaced
- Fix devcontainer postCreateCommand to install correct leptonica package
  (libleptonica6 + symlink) for image-tools-mcp on Debian Trixie

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: ironsheep

.devcontainer/devcontainer.json

@@ -4,8 +4,9 @@
   "dockerComposeFile": ["docker-compose.yml", "docker-compose.override.yml"],
   "service": "dev",
   "workspaceFolder": "/workspaces/PNut-Term-TS",
+  "remoteUser": "node",
   "initializeCommand": "test -f .devcontainer/docker-compose.override.yml || echo 'services: {}' > .devcontainer/docker-compose.override.yml",
-  "postCreateCommand": "sudo apt-get update && sudo apt-get install -y liblept5 libtesseract5 || true; sudo mkdir -p /Users/stephen && sudo ln -sfn /opt/container-tools /Users/stephen/container-tools; npm install && if [ -f .devcontainer/install-claude-local.sh ]; then bash .devcontainer/install-claude-local.sh; fi",
+  "postCreateCommand": "sudo apt-get update && sudo apt-get install -y libleptonica6 libtesseract5 && LEPLIB=$(find /lib -name 'libleptonica.so.*' -not -name '*.so.*.*' | head -1) && sudo ln -sf \"$LEPLIB\" \"$(dirname $LEPLIB)/liblept.so.5\" && sudo ldconfig || true; sudo mkdir -p /Users/stephen && sudo ln -sfn /opt/container-tools /Users/stephen/container-tools; npm install && if [ -f .devcontainer/install-claude-local.sh ]; then bash .devcontainer/install-claude-local.sh; fi",
   "customizations": {
     "vscode": {
       "extensions": [

CHANGELOG.md

@@ -5,6 +5,16 @@ All notable changes to PNut-Term-TS will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [0.9.23] - 2026-03-09
+
+### Fixed
+
+- **Application process not exiting on Fedora Linux** - Closing all windows left the Electron process running invisibly in the background, holding the serial port open and requiring `kill -9` to free it for the next session
+  - Removed a duplicate `window-all-closed` handler that raced with serial port cleanup, calling `app.quit()` before the port was properly closed
+  - Added a 5-second safety timeout so the process exits even if serial port cleanup hangs
+- **CR-only line endings overwrite lines in PST terminal** - Programs written for Parallax Serial Terminal that terminate lines with CR only (no LF) had every line overwritten in place, because CR was treated as carriage return without line feed
+  - CR now implies LF in PST mode, matching Parallax Serial Terminal behavior; programs sending CR+LF are not double-spaced
+
 ## [0.9.22] - 2026-03-06
 
 ### Fixed