Adversarial review of this PR found that pinning the runner format per script
reopened issue #6896 one layer down.
- `WorktreeSetupLaunch.shell` had been redefined to mean "the format the runner
file was written in". `resolveSetupRunnerCommand` consumes it as "the shell
that types the launch command", so a Git Bash terminal with a batch setup
script produced `cmd.exe /c "C:\...\setup-runner.cmd"` typed into a bash pane,
where MSYS rewrites the `/c` switch into a drive path: cmd opens interactively
and setup never runs. `shell` is the terminal's family again; the runner file's
.cmd/.sh extension carries the format, and a batch runner launched from a POSIX
pane reuses the existing PowerShell ProcessStartInfo launcher.
- The cmd runner dropped a leading `#!` line and ran the rest as batch, so a bash
script reaching cmd (PowerShell/cmd terminal, or any SSH-to-Windows host) got
its interpreter-agnostic prefix executed before failing mid-way. It now prints
why and exits 1 without running anything.
- A `#!` line's option flags were discarded: `#!/usr/bin/env -S bash -euo
pipefail` lost pipefail because the runner is launched as `bash <path>`. The
generated posix runner now replays declared flags via `set` and drops the
duplicate interpreter line.
- Docs cover the per-user setup command in repository hook settings, which goes
through the same `#!` rule, and describe what the `#!` line does and does not
select.
Tests: composed launch command for a POSIX pane + cmd runner (hooks, shared
runner command, setup sequencing gate, observed-setup signal), the cmd runner's
shebang refusal, and shebang flag replay. Each fails with the source reverted.
#6967 derived the Windows setup-runner shell from `terminalWindowsShell`. On
upgrade, any Windows user whose terminal preference resolved to Git Bash had
their existing `orca.yaml` setup script (and issue command) handed to bash
instead of cmd.exe. Scripts authored against the cmd runner — `copy`, `xcopy`,
`set VAR=value`, `if errorlevel 1`, `%VAR%`, backslash paths — broke with no
migration and no warning, and the failure looked like Orca broke the project.
The conflation is also wrong in the steady state: a terminal preference is
per-user, so two people on the same repo got different interpreters for the
same orca.yaml and no project could write a setup script that worked for all
of its Windows contributors.
The interpreter is now a property of the script, declared the standard way:
a leading `#!` line. Native Windows keeps the historical `.cmd` runner unless
the script declares a POSIX shell, so no existing script changes behavior.
`resolveSetupRunnerShell` keeps its role as the feasibility gate — a bash
runner still requires the terminal to resolve to Git Bash, since the launch
command is typed into that shell and uses MSYS `/c/...` paths.
`buildWindowsRunnerScript` now drops a leading `#!` line rather than `call`ing
it, so a declared-bash script that falls back to cmd (Git Bash missing) fails
on a real setup line instead of aborting on errorlevel at line one.
WSL worktrees, POSIX platforms, and SSH hosts are untouched.
OrcaWin