QuickTerm v3.10.0

Fixes for the 55 issues filed by the September audit (#9 to #63).

Terminals that stay usable under load

• On Linux, pasting a lot into a busy program froze every pane, the REST API
  and the WebSocket until the program read its input. The writer no longer
  holds the terminal while it waits.
• Fast output (yes, a big build) made the Linux viewer reset and replay the
  terminal hundreds of times a second. Output is now collected into large
  chunks as on Windows, and a viewer is only resynchronised once it is 2 MiB
  behind instead of eight reads behind. The throughput benchmark went from
  failing every run to about 55 MB/s.
• Re-opening a terminal after its scrollback wrapped could print stray
  characters and switch off modes set at startup. Replay now never starts in
  the middle of an escape sequence or a character, and restores bracketed
  paste, the alternate screen, mouse reporting and cursor modes, so a long
  Claude Code session keeps working after a reload or a workspace switch.

Kill, exit and cleanup

• On Linux, killing a terminal now ends every job in it, including background
  jobs, and a shell that exits while a background job still holds the
  terminal is reported as exited at once.
• A kill that fails leaves the terminal able to take input.
• On Windows, a kill is only reported as done when every process of the tree
  is gone.
• The idle reaper rechecks each terminal right before it stops it, so a
  terminal you open or type into during a cleanup pass survives.
• A detached terminal that finishes while you are away keeps its final output
  until you open it (up to 24 hours).
• Automatic replies from the terminal (cursor position, focus reports) no
  longer count as typing, so an untouched shell can be cleaned up and no
  longer keeps QuickTerm in the tray.

Starting terminals

• A missing program now says which terminal and which command failed, with a
  hint that QuickTerm reads PATH when it starts, instead of "Internal Server
  Error".
• PowerShell and Command Prompt profiles use the executable the inventory
  found and keep their own arguments. Git Bash and Nushell profiles run their
  start command.
• Autostart and global-hotkey profiles resolve exactly like terminals started
  from the sidebar, get the PuTTY tools on PATH, and report a failure in the
  error banner instead of failing silently.
• A profile that sets Path now really replaces PATH on Windows.
• Linux terminals always advertise TERM=xterm-256color and truecolor.
• On Windows, QuickTerm no longer runs a taskkill.exe or shell planted in
  the folder "Open QuickTerm here" was used on.

Workspaces, windows and settings

• "Open QuickTerm here" within 20 seconds of a reload is no longer lost.
• Deleting a workspace while an autosave is running no longer brings it back.
• A partial settings save no longer wipes profiles and their secrets, and
  every save keeps the previous file as config.prev.json.
• Changing the port back to its old value now sticks.
• A hidden or minimized window keeps its workspace claim.
• An administrator window keeps its own workspaces and no longer deletes the
  normal window's scratch layout.
• A corrupt workspace file is set aside as *.invalid-*.json instead of
  becoming an entry that cannot be opened or deleted. Workspace names such as
  con.txt save on Windows 10.
• A workspace autosave without a logo no longer clears the logo.
• Settings > General has a Scratch folder field.
• Splits on Linux open in the pane's real folder instead of a \\host\path
  UNC path.