feat(worker): run worker as per-user logon task instead of Windows service

A LocalSystem Windows service can't see the logged-in user's Claude CLI
authentication, so the worker now runs as the current user via a hidden
per-user logon Scheduled Task with restart-on-failure.

- Worker is WinExe (no console window) with a Serilog rolling file sink and
  a single-instance mutex so the logon task, app ensure-running, and Restart
  button can't fight over the SignalR port.
- Installer replaces the service steps (register/start/stop) with autostart
  task steps, migrates the legacy ClaudeDoWorker service away on update, and
  removes the task on uninstall. ServicePage drops the service-account UI.
- UI gains a WorkerLocator; the app ensures the worker is running at startup
  and the Restart button kills+relaunches this install's worker process.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

docs/superpowers/specs/2026-05-29-worker-per-user-autostart-design.md

@@ -0,0 +1,165 @@
+# Worker per-user autostart (drop Windows service)
+
+Status: approved 2026-05-29
+Author: brainstorm session (mika kuns + Claude)
+
+## Problem
+
+The worker runs as a Windows **service** registered under `LocalSystem`. The worker
+shells out to the `claude` CLI, whose authentication is stored per-user
+(`%USERPROFILE%\.claude`). Under `LocalSystem` the worker uses the system profile and
+cannot see the user's Claude login, so task execution fails. The installer even exposes a
+"Current User" service-account radio that the backend rejects (`RegisterServiceStep`
+fails the install). Net effect: the only installable configuration cannot authenticate
+Claude.
+
+## Goal
+
+Run the worker as the logged-in **user** so it inherits the user's Claude auth, starting
+automatically at logon and staying alive in the background (independent of the desktop
+app, so Prime/scheduled tasks fire when the UI is closed).
+
+## Decisions (locked)
+
+1. **Lifetime:** background from logon, always — independent of the UI.
+2. **Mechanism:** per-user **logon Scheduled Task** (`schtasks`), run only when the user is
+   logged on (no stored password), hidden, with restart-on-failure.
+3. **No console window:** worker becomes `WinExe`; add a **Serilog rolling file sink** so
+   worker diagnostics aren't lost.
+4. **App ensures running:** "Restart Worker" becomes process-based; on app startup, if
+   SignalR doesn't connect within a few seconds, the app launches the worker.
+5. **Auto-migrate:** the installer detects and removes the old `ClaudeDoWorker` service,
+   then registers the task. Uninstall removes the task + kills the worker process.
+
+## Non-goals
+
+- Cross-account elevation (admin elevates as a *different* account than the interactive
+  user). Single-user / user-is-admin is assumed; the task targets the interactive user.
+- Running the worker when no user is logged on (that's the whole point — it must be a user
+  session for Claude auth).
+
+---
+
+## Component changes
+
+### ClaudeDo.Worker
+
+- **`ClaudeDo.Worker.csproj`**: `<OutputType>WinExe</OutputType>`. Add packages
+  `Serilog.AspNetCore` and `Serilog.Sinks.File`.
+- **`Program.cs`**:
+  - Remove `builder.Host.UseWindowsService(...)`.
+  - Configure Serilog file sink: path `<LogRoot>/worker-.log`, `rollingInterval: Day`,
+    `retainedFileCountLimit: 7`, shared write. `LogRoot` comes from `WorkerConfig`
+    (expand `~`). Wire via `builder.Host.UseSerilog(...)`.
+  - **Single-instance guard:** at startup create `new Mutex(true, @"Local\ClaudeDoWorker",
+    out var createdNew)`. If `!createdNew`, log "another worker instance is already
+    running" and exit 0. Hold the mutex for process lifetime. `Local\` namespace = per
+    user session, which is what we want.
+- CLI preflight (`ClaudeCliPreflight`) behavior unchanged.
+
+### ClaudeDo.Installer
+
+- **New `Steps/RegisterAutostartStep.cs`** (`IInstallStep`, "Register Autostart"):
+  - Build a Task Scheduler **definition XML** (UTF-16) and register via
+    `schtasks /Create /TN "ClaudeDoWorker" /XML "<tmpfile>" /F`.
+  - XML shape:
+    - `Principals/Principal`: `UserId` = current interactive user
+      (`WindowsIdentity.GetCurrent().Name`), `LogonType=InteractiveToken`,
+      `RunLevel=LeastPrivilege`.
+    - `Triggers/LogonTrigger` with the same `UserId`.
+    - `Settings`: `Hidden=true`, `MultipleInstancesPolicy=IgnoreNew`,
+      `StartWhenAvailable=true`, `ExecutionTimeLimit=PT0S`,
+      `DisallowStartIfOnBatteries=false`, `StopIfGoingOnBatteries=false`,
+      `RestartOnFailure` with `Interval` (>= `PT1M`; Task Scheduler's minimum granularity
+      is one minute) and `Count=3`.
+    - `Actions/Exec/Command`: quoted path to `<installDir>/worker/ClaudeDo.Worker.exe`.
+  - The XML builder is a **pure function** (string in → XML string out) so it is unit
+    testable without admin.
+- **`MigrateServiceStep`** (or folded into `RegisterAutostartStep` as a first phase):
+  detect the old service via `sc query ClaudeDoWorker`; if present, `sc stop` then
+  `sc delete` (poll for clearance like the old `RegisterServiceStep` did). No-op when the
+  service doesn't exist (fresh installs).
+- **Rename `StopServiceStep` → `StopWorkerStep`, `StartServiceStep` → `StartWorkerStep`**,
+  reworked to be process/task based:
+  - Stop: `schtasks /End /TN ClaudeDoWorker` (ignore errors) + kill any
+    `ClaudeDo.Worker` process whose `MainModule.FileName` is under the install dir;
+    wait for exit. This unlocks `worker/` binaries before extract.
+  - Start: `schtasks /Run /TN ClaudeDoWorker` (preferred — launches as the task principal).
+    Used by fresh install (so the worker runs immediately rather than waiting for next
+    logon) and by Settings "restart".
+- **`Pages/ServicePage/ServicePageViewModel.cs`**: remove `IsLocalSystem`/`IsCurrentUser`
+  radios and `ServiceAccount` usage. Keep SignalR port, Claude CLI path, "Start at logon"
+  toggle (`AutoStart`), restart delay (maps to task `RestartOnFailure/Interval`, clamped
+  to >= 1 min). Update `ServicePageView.xaml` accordingly. Remove `ServiceAccount` from
+  `InstallContext`.
+- **`RegisterServiceStep.cs`**: deleted (replaced by `RegisterAutostartStep`).
+- **Pipelines (`InstallPageViewModel`)**:
+  - Fresh: DownloadAndExtract → WriteConfig → InitDatabase → **RegisterAutostart** (incl.
+    migration no-op) → CreateShortcuts → WriteUninstallRegistry → WriteInstallManifest →
+    **StartWorker**.
+  - Update: **StopWorker** → DownloadAndExtract → **RegisterAutostart** (migrates old
+    service) → **StartWorker** → WriteInstallManifest → WriteUninstallRegistry.
+- **DI (`App.xaml.cs`)**: register the renamed/new steps (concrete + `IInstallStep` where
+  needed, following the existing double-registration pattern).
+- **`Core/UninstallRunner.cs`**: replace `sc delete ClaudeDoWorker` with
+  `schtasks /Delete /TN ClaudeDoWorker /F` and kill the worker process; also `sc delete`
+  the legacy service best-effort (in case an old service still lingers).
+
+### ClaudeDo.Ui / ClaudeDo.App
+
+- **New `Services/WorkerLocator.cs`**: resolve `<installDir>/worker/ClaudeDo.Worker.exe`
+  by walking up for `install.json` then registry `InstallLocation` (mirrors
+  `InstallerLocator`).
+- **`ViewModels/IslandsShellViewModel.cs`**:
+  - `RestartWorkerService`: drop `System.ServiceProcess.ServiceController`. Kill worker
+    process(es) under the install dir, then `Process.Start(workerExe)`.
+  - **Ensure-running:** on startup, if the `WorkerClient` connection isn't established
+    within ~4s, launch the worker via `WorkerLocator` + `Process.Start`. Guarded so it
+    runs at most once per app session.
+- Remove the `System.ServiceProcess` package reference / usings if no longer used.
+
+---
+
+## Data flow
+
+- **Logon:** Task Scheduler starts `ClaudeDo.Worker.exe` in the user session → mutex
+  acquired → Serilog file logging → SignalR hub on `127.0.0.1:47821` → app connects.
+- **App start with worker down:** app waits ~4s for SignalR; if absent, `Process.Start`
+  worker → mutex acquired → hub up → app connects.
+- **Duplicate launch (task + app race):** second instance fails the mutex → logs → exits 0.
+- **Restart Worker button:** kill worker proc → relaunch → mutex reacquired.
+
+## Error handling
+
+- `schtasks`/`sc` calls go through the existing `ProcessRunner`; non-zero exits surface as
+  `StepResult.Fail` with the captured output (except best-effort cleanup which is ignored).
+- Worker single-instance: losing the mutex is a normal, non-error exit (code 0).
+- App ensure-running: `Process.Start` failures are swallowed (the logon task is the primary
+  mechanism; the app launch is a convenience).
+
+## Testing
+
+- **Unit (no admin required):**
+  - Task-definition XML builder: asserts UserId, LogonType, Hidden, RestartOnFailure
+    interval clamping, quoted command path.
+  - `WorkerLocator`: path resolution via temp `install.json`.
+  - Migration decision: given `sc query` output (exists / not-found), decide stop+delete vs
+    no-op — keep the decision pure, mock `ProcessRunner` output.
+  - Restart-delay → task interval clamping (`< 1 min` → `PT1M`).
+- **Manual verification (post-build, on this machine):**
+  1. Update from installed `1.0.2-alpha`: old service is removed (`sc query ClaudeDoWorker`
+     → not found), task exists (`schtasks /Query /TN ClaudeDoWorker`), worker process runs
+     as the user, app connects, no console window.
+  2. Worker log file appears at `~/.todo-app/logs/worker-<date>.log`.
+  3. Kill worker → click Restart Worker in app → reconnects.
+  4. Close app, confirm worker still running (Prime/queue alive); reopen app → connects.
+  5. Log off / log on → worker autostarts.
+  6. Uninstall → task gone, worker process gone, (data kept unless opted out).
+
+## Risks
+
+- **Task restart granularity is minutes**, not the old seconds-level service restart. The
+  worker's own long-running resilience + the app ensure-running cover short gaps; acceptable.
+- **Elevated installer must target the interactive user.** Using
+  `WindowsIdentity.GetCurrent().Name` is correct when the user elevates themselves (the
+  assumed single-user case). Documented non-goal otherwise.