Add SessionEnd hook for terminal cleanup as defense-in-depth

[Trecek]

Summary

Add a Claude Code SessionEnd hook that emits terminal reset escape sequences when a session ends. This provides defense-in-depth alongside terminal_guard() — the hook fires from inside Claude Code's exit path, covering cases where terminal_guard() might not execute (SIGTERM, etc.).

Proposed Configuration

Add to ~/.claude/settings.json (user-level, applies to all Claude Code sessions):

{
  "hooks": {
    "SessionEnd": [
      {
        "type": "command",
        "command": "printf '\\e[?2004l\\e[?1l\\e[?25h\\e[=0u\\e[<99u\\e[?1000l\\e[?1003l\\e[?1006l\\e[J'"
      }
    ]
  }
}

Why Human Review

This is a user-level configuration change, not a code change:

• Goes in ~/.claude/settings.json, not in the project codebase
• Affects ALL Claude Code sessions (not just autoskillit cook/order)
• Needs human decision on whether this should be:
  • Documented as a recommended setup step
  • Added to the autoskillit install flow
  • Added to the autoskillit doctor checks
  • Left as optional guidance in docs

Relationship to #676

Issue #676 implements the code-level fix in terminal_guard(). This issue adds a complementary layer that fires from inside Claude Code itself. The two are independent — each covers gaps the other can't reach. The escape sequences are idempotent, so double-emission is harmless.

Investigation Report

.autoskillit/temp/investigate/investigation_terminal-state-corruption-after-cook-exit_2026-04-08_183000.md