fix(gui-extensions): WSL probeDistro reads bash/curl verdict by whole-output equality — a login-shell banner reports installed tools as missing #269

Problem

WSL probeDistro decides whether a distro has bash and curl by comparing the entire login-shell output to exactly "yes". Any banner, MOTD, or .profile echo printed by the login shell makes a distro that has both tools report hasBash: false / hasCurl: false.

packages/gui-extensions/src/wsl/runtime.ts:328-337 (on main ebd31d02d3):

const [bash, curl] = await Promise.all([
  runWslSh("command -v bash >/dev/null && printf yes || printf no", name, opts),
  runWslSh("command -v curl >/dev/null && printf yes || printf no", name, opts),
])

return {
  ...
  hasBash: bash.code === 0 && summarize(bash.stdout) === "yes",
  hasCurl: curl.code === 0 && summarize(curl.stdout) === "yes",
  ...
}

Both probes run through runWslSh (runtime.ts:223-224), which is sh -lc — a login shell, so profile/banner output on stdout is expected, not exotic. And summarize (runtime.ts:57-64) does not drop it: it trims each line, drops empty lines, and joins the rest with \n, preserving every banner line.

Reproduction (the exact summarize logic run under node)

Impact

• packages/gui-extensions/src/wsl/model.ts:60 — wslDistroReady requires probe.hasBash && probe.hasCurl, so the distro can never become ready and no server can be added for it.
• packages/gui-extensions/src/wsl/model.ts:174 — the onboarding status shows the "missing tools" warning for a distro whose tools are installed.
• packages/gui-extensions/src/wsl/servers.ts:414-415 — distroProbeReady gates the opencode CLI check (inspectCli), so the CLI check never runs for such a distro either.

Relationship to #265

#265 covers the sibling login-shell parsers in the same transport — parseVersion in both remote-cli.ts copies and WSL resolveCli. Its acceptance criteria do not mention probeDistro; this is the remaining exact-match probe in wsl/runtime.ts (verified: the only two summarize(...) === "yes" sites in the repo are lines 336-337, and no copy of this probe exists in developing-today/code, developing-today/openchamber, or dezren39/nix). Fixing it alongside #265 is welcome, but it should not be lost if #265 closes without it.

Acceptance criteria

• probeDistro's bash/curl verdicts are read from the probe script's own answer line (the final non-empty line the script prints, yes or no), not from whole-output equality — banner/MOTD/profile lines before it must not change the verdict.
• A banner line that itself contains the word yes must not produce a false positive when the script's answer is no (read the answer line, not any line).
• New unit tests cover: clean yes, clean no, banner-before-yes → true, banner-before-no → false. (The probe verdict logic will likely need to be a pure exported helper to be testable, as createWslRuntime spawns real wsl.exe.)
• Clean-output behaviour is unchanged: a distro whose login shell prints nothing extra gets the same probe result as today.

Filed by new-issue-creator after verifying on main ebd31d02d3 (file:line reads, node repro of the exact summarize logic, dedup searches for probeDistro / hasBash / hasCurl and a full read of #265's acceptance criteria returned no covering issue).