- .zprofile/.zshrc/.zlogin each define __orca_resolve_user_config_dir. They
called it on line 2 while only .zshenv defined it, so a wrapper dir written by
two concurrently installed builds printed three "command not found" and
skipped the user's entire zsh config. New live-shell test covers it.
- Retarget every remaining ORCA_SHELL_READY_MARKER/ORCA_SHELL_STARTUP_IDENTITY
reference onto ORCA_SHELL_FEATURES, or delete it where the key is now dead.
- isOrcaMintedHistFile requires a leading '/', so a relative path of the same
shape stays the user's.
- Drop an unused no-control-regex disable, and register the two real-zsh suites
in the dedicated shell-contracts lane.