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>

skills/brainstorming/scripts/start-server.sh

@@ -106,6 +106,12 @@ if [[ -z "$OWNER_PID" || "$OWNER_PID" == "1" ]]; then
   OWNER_PID="$PPID"
 fi
 
+# On Windows/MSYS2, the MSYS2 PID namespace is invisible to Node.js.
+# Skip owner-PID monitoring — the 30-minute idle timeout prevents orphans.
+case "${OSTYPE:-}" in
+  msys*|cygwin*|mingw*) OWNER_PID="" ;;
+esac
+
 # Foreground mode for environments that reap detached/background processes.
 if [[ "$FOREGROUND" == "true" ]]; then
   echo "$$" > "$PID_FILE"

skills/brainstorming/visual-companion.md

@@ -48,12 +48,21 @@ Save `screen_dir` from the response. Tell user to open the URL.
 
 **Launching the server by platform:**
 
-**Claude Code:**
+**Claude Code (macOS / Linux):**
 ```bash
 # Default mode works — the script backgrounds the server itself
 scripts/start-server.sh --project-dir /path/to/project
 ```
 
+**Claude Code (Windows):**
+```bash
+# Windows auto-detects and uses foreground mode, which blocks the tool call.
+# Use run_in_background: true on the Bash tool call so the server survives
+# across conversation turns.
+scripts/start-server.sh --project-dir /path/to/project
+```
+When calling this via the Bash tool, set `run_in_background: true`. Then read `$SCREEN_DIR/.server-info` on the next turn to get the URL and port.
+
 **Codex:**
 ```bash
 # Codex reaps background processes. The script auto-detects CODEX_CI and
@@ -61,14 +70,6 @@ scripts/start-server.sh --project-dir /path/to/project
 scripts/start-server.sh --project-dir /path/to/project
 ```
 
-**Windows (Git Bash / CMD / PowerShell):**
-```bash
-# Windows/Git Bash reaps nohup background processes. The script auto-detects
-# this via OSTYPE/MSYSTEM and switches to foreground mode automatically.
-# No extra flags needed — all Windows shells route through Git Bash.
-scripts/start-server.sh --project-dir /path/to/project
-```
-
 **Gemini CLI:**
 ```bash
 # Use --foreground and set is_background: true on your shell tool call

skills/writing-plans/SKILL.md

@@ -49,7 +49,7 @@ This structure informs the task decomposition. Each task should produce self-con
 ```markdown
 # [Feature Name] Implementation Plan
 
-> **For agentic workers:** REQUIRED: Use superpowers:subagent-driven-development (if subagents available) or superpowers:executing-plans to implement this plan. Steps use checkbox (`- [ ]`) syntax for tracking.
+> **For agentic workers:** REQUIRED SUB-SKILL: Use superpowers:subagent-driven-development (recommended) or superpowers:executing-plans to implement this plan task-by-task. Steps use checkbox (`- [ ]`) syntax for tracking.
 
 **Goal:** [One sentence describing what this builds]
 
@@ -126,17 +126,20 @@ After writing the complete plan:
 
 ## Execution Handoff
 
-After saving the plan:
+After saving the plan, offer execution choice:
 
-**"Plan complete and saved to `docs/superpowers/plans/<filename>.md`. Ready to execute?"**
+**"Plan complete and saved to `docs/superpowers/plans/<filename>.md`. Two execution options:**
 
-**Execution path depends on harness capabilities:**
+**1. Subagent-Driven (recommended)** - I dispatch a fresh subagent per task, review between tasks, fast iteration
 
-**If harness has subagents (Claude Code, etc.):**
-- **REQUIRED:** Use superpowers:subagent-driven-development
-- Do NOT offer a choice - subagent-driven is the standard approach
+**2. Inline Execution** - Execute tasks in this session using executing-plans, batch execution with checkpoints
+
+**Which approach?"**
+
+**If Subagent-Driven chosen:**
+- **REQUIRED SUB-SKILL:** Use superpowers:subagent-driven-development
 - Fresh subagent per task + two-stage review
 
-**If harness does NOT have subagents:**
-- Execute plan in current session using superpowers:executing-plans
+**If Inline Execution chosen:**
+- **REQUIRED SUB-SKILL:** Use superpowers:executing-plans
 - Batch execution with checkpoints for review