SessionStart hook fragile on Windows/MSYS due to set -euo pipefail

[hmseeb]

Environment: Windows (MSYS_NT-10.0), Claude Code, superpowers v4.3.0

Problem: The hooks/session-start.sh hook intermittently fails on Windows/MSYS with a SessionStart:startup hook error. The likely cause is set -euo pipefail (line 4), which makes the script exit on any error — including edge cases in path resolution (BASH_SOURCE, dirname) or unset variables that can occur transiently on MSYS/Git Bash.

Suggestion: Since the hook provides optional context injection and already has a fallback for the cat on line 18 (|| echo "Error reading..."), consider either:

• Removing set -euo pipefail entirely, or
• Replacing it with softer guards (e.g., set -e only, with explicit || true on fragile operations)

The script unconditionally does exit 0 at line 46, so removing strict mode won't mask real failures — it'll just prevent transient MSYS quirks from blocking context injection.