fix: Windows brainstorm server lifecycle, restore execution choice

- Skip OWNER_PID monitoring on Windows/MSYS2 where the PID namespace is
  invisible to Node.js, preventing server self-termination after 60s (#770)
- Document run_in_background: true for Claude Code on Windows (#767)
- Restore user choice between subagent-driven and inline execution after
  plan writing; subagent-driven is recommended but no longer mandatory
- Add Windows lifecycle test script verified on Windows 11 VM
- Note #723 (stop-server.sh reliability) as already fixed

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

CHANGELOG.md

@@ -5,10 +5,16 @@
 ### Fixed
 
 - **Brainstorm server on Windows**: Auto-detect Windows/Git Bash (`OSTYPE=msys*`, `MSYSTEM`) and switch to foreground mode, fixing silent server failure caused by `nohup`/`disown` process reaping. Applies to all Windows shells (CMD, PowerShell, Git Bash) since they all route through Git Bash. ([#737](https://github.com/obra/superpowers/issues/737), based on [#740](https://github.com/obra/superpowers/pull/740))
+- **Brainstorm owner-PID on Windows**: Skip `BRAINSTORM_OWNER_PID` lifecycle monitoring on Windows/MSYS2 where the PID namespace is invisible to Node.js. Prevents the server from self-terminating after 60 seconds. The 30-minute idle timeout remains as the safety net. ([#770](https://github.com/obra/superpowers/issues/770))
 - **Portable shebangs**: Replace `#!/bin/bash` with `#!/usr/bin/env bash` in all 13 shell scripts. Fixes execution on NixOS, FreeBSD, and macOS with Homebrew bash where `/bin/bash` is outdated or missing. ([#700](https://github.com/obra/superpowers/pull/700), dupes: [#747](https://github.com/obra/superpowers/pull/747))
 - **POSIX-safe hook script**: Replace `${BASH_SOURCE[0]:-$0}` with `$0` in `hooks/session-start` and polyglot-hooks docs. Fixes 'Bad substitution' error on Ubuntu/Debian where `/bin/sh` is dash. ([#553](https://github.com/obra/superpowers/pull/553))
 - **Bash 5.3+ hook hang**: Replace heredoc (`cat <<EOF`) with `printf` in `hooks/session-start`. Fixes indefinite hang on macOS with Homebrew bash 5.3+ caused by a bash regression with large variable expansion in heredocs. ([#572](https://github.com/obra/superpowers/pull/572), [#571](https://github.com/obra/superpowers/issues/571))
 - **Cursor hooks support**: Add `hooks/hooks-cursor.json` with Cursor's camelCase format (`sessionStart`, `version: 1`) and update `.cursor-plugin/plugin.json` to reference it. Fix platform detection in `session-start` to check `CURSOR_PLUGIN_ROOT` first (Cursor may also set `CLAUDE_PLUGIN_ROOT`). (Based on [#709](https://github.com/obra/superpowers/pull/709))
+- **stop-server.sh reliability**: Verify the server process actually died before reporting success. Waits up to 2 seconds for graceful shutdown, escalates to `SIGKILL`, and reports failure if the process survives. ([#723](https://github.com/obra/superpowers/issues/723))
+
+### Changed
+
+- **Execution handoff**: Restore user choice between subagent-driven-development and executing-plans after plan writing. Subagent-driven is recommended but no longer mandatory. (Reverts `5e51c3e`)
 
 ### Already fixed on dev (closed PRs)
 
@@ -17,4 +23,4 @@
 
 ### Known Issues
 
-- **`BRAINSTORM_OWNER_PID` on Windows (main branch only)**: The main branch's `server.js` uses `process.kill(OWNER_PID, 0)` for lifecycle checks, but receives MSYS2 PIDs which are invisible to Node.js (different PID namespace). This causes the server to self-terminate after 60 seconds. Fix: resolve `OWNER_PID` via `/proc/$PPID/winpid` to get the Windows-native PID. The dev branch's `index.js` does not have this issue since it has no OWNER_PID lifecycle check.
+(None currently tracked.)