Judge the probes on the desktop's deadline, and interrupt the host it uses

Preflight gives each managed probe ten seconds and nothing more: managed.rs:337
wraps `unsloth -h` and managed.rs:390 wraps `studio desktop-capabilities --json`
in a tokio timeout, kills the child on expiry, and returns Stale as
"cli_unusable" or "desktop_capability_probe_failed". The probe allowed three
minutes, so a venv torn badly enough that its CLI only answers after half a
minute of retries was recorded HEALTHY here while the real app shows it as
repairable. That skips the re-run assertion the leg exists to make, which is the
same false-HEALTHY hole the studio_install_ok and -h gating already closed. Both
calls now use the desktop's ten seconds, and the elapsed time is recorded so a
leg that flips for timing reasons says so in the artefact.

On Windows the installer child now runs where the desktop runs it. install.rs
325-339 spawns the bundled install.ps1 as powershell.exe with -NoLogo -NoProfile
-NonInteractive -WindowStyle Hidden -ExecutionPolicy Bypass -File, so Windows
PowerShell 5.1 is the only host a real desktop install ever uses. The interrupted
run and the repair re-run both used pwsh 7, and every other Windows job in
.github runs install.ps1 under pwsh too, so the installer's behaviour on 5.1 was
covered by nothing: .NET Framework instead of .NET, OEM console encoding instead
of UTF-8, and different native-command and OSArchitecture reporting are all real
sources of divergence. A workflow whose point is to reproduce what the app does
cannot run a different interpreter than the app does. The driver itself stays
under pwsh; only the installer child and the repair invocation change.

.github/scripts/interrupt-install.ps1

@@ -41,10 +41,25 @@ foreach ($dir in @($env:UNSLOTH_STUDIO_HOME, (Join-Path $HOME '.unsloth\studio')
   } catch { Write-Host "[interrupt] could not seed install marker in ${dir}: $_" }
 }
 
-# Run the installer in its own pwsh so stdout can be redirected to the log while we poll.
-$argList = @('-NoProfile', '-NonInteractive', '-File', 'install.ps1')
+# Run the installer in its own host so stdout can be redirected to the log while we
+# poll. That host is WINDOWS PowerShell, not pwsh: the desktop app spawns the bundled
+# install.ps1 as `powershell.exe -NoLogo -NoProfile -NonInteractive -WindowStyle Hidden
+# -ExecutionPolicy Bypass -File` (install.rs:325-339), so 5.1 with those flags is the
+# only host a real desktop install ever uses. Every other Windows job in .github runs
+# install.ps1 under the runner's pwsh 7, which leaves the installer's behaviour on 5.1
+# -- .NET Framework rather than .NET, OEM/ANSI console encoding rather than UTF-8,
+# different native-command and OSArchitecture reporting -- covered by nothing. An
+# interruption test that runs a different interpreter than the app cannot claim to
+# reproduce what the app does. The driver itself stays under pwsh; only the installer
+# child and the repair re-run change.
+$argList = @(
+  '-NoLogo', '-NoProfile', '-NonInteractive',
+  '-WindowStyle', 'Hidden',
+  '-ExecutionPolicy', 'Bypass',
+  '-File', 'install.ps1'
+)
 if ($InstallArgs) { $argList += $InstallArgs.Split(' ') }
-$proc = Start-Process -FilePath 'pwsh' -ArgumentList $argList `
+$proc = Start-Process -FilePath 'powershell.exe' -ArgumentList $argList `
   -RedirectStandardOutput $LogPath -RedirectStandardError "$LogPath.err" `
   -PassThru -NoNewWindow
 Write-Host "[interrupt] installer pid=$($proc.Id) marker='$Marker' deadline=${KillAtSeconds}s"

.github/scripts/interrupted_install_probe.py

@@ -95,18 +95,33 @@ def main(argv: list[str]) -> int:
         print(f"[probe] {k:28} = {v}")
 
     # ── the two probes Tauri preflight actually runs ─────────────────────────
-    r = run([binp, "-h"], timeout = 180)
+    # Both under the DESKTOP's deadline, not a generous CI one. preflight wraps each
+    # call in a 10 second tokio timeout (managed.rs:337 for `-h`, managed.rs:390 for
+    # desktop-capabilities) and on expiry kills the child and reports Stale --
+    # "cli_unusable" or "desktop_capability_probe_failed" (managed.rs:471, :521). A
+    # torn venv whose CLI still answers, but only after 30 seconds of import retries,
+    # is therefore an install the app sends to repair; waiting three minutes for it
+    # here would call the same install HEALTHY and skip the re-run assertion. run()
+    # reports a timeout as a non-zero rc, which lands in the same REPAIRABLE arm the
+    # desktop's Stale maps to.
+    PREFLIGHT_TIMEOUT = 10
+
+    t0 = time.time()
+    r = run([binp, "-h"], timeout = PREFLIGHT_TIMEOUT)
     (out / "cli-h.log").write_text(merged(r), encoding = "utf-8", errors = "replace")
     say("cli_h_ok", r[0] == 0)
+    say("cli_h_seconds", round(time.time() - t0, 2))
 
+    t0 = time.time()
     caps_rc, caps_out, caps_err = run(
-        [binp, "studio", "desktop-capabilities", "--json"], timeout = 180
+        [binp, "studio", "desktop-capabilities", "--json"], timeout = PREFLIGHT_TIMEOUT
     )
     (out / "desktop-capabilities.json").write_text(caps_out, encoding = "utf-8", errors = "replace")
     (out / "desktop-capabilities.stderr.log").write_text(
         caps_err, encoding = "utf-8", errors = "replace"
     )
     say("capabilities_ok", caps_rc == 0)
+    say("capabilities_seconds", round(time.time() - t0, 2))
 
     # Parse EXACTLY as the desktop does: managed.rs:414 hands the whole stdout buffer
     # to serde_json, which rejects any leading or trailing non-JSON, and stderr was

.github/workflows/interrupted-install-ci.yml

@@ -293,7 +293,12 @@ jobs:
         if: always() && steps.probe.outputs.verdict != 'HEALTHY'
         shell: pwsh
         run: |
-          pwsh -NoProfile -NonInteractive -File install.ps1 ${{ matrix.installArgs }} *>&1 |
+          # powershell.exe with install.rs:325-339's flags, matching the interrupted
+          # run: the desktop repairs by re-running the same bundled script in Windows
+          # PowerShell 5.1, so a repair that only works under pwsh 7 would pass here
+          # and still strand the user.
+          powershell.exe -NoLogo -NoProfile -NonInteractive -WindowStyle Hidden `
+            -ExecutionPolicy Bypass -File install.ps1 ${{ matrix.installArgs }} *>&1 |
             Tee-Object -FilePath logs/repair.log
           $bin = Join-Path $env:USERPROFILE '.unsloth\studio\unsloth_studio\Scripts\unsloth.exe'
           if (-not (Test-Path $bin)) {