feat: install bundled Pi control skill during setup

[almogdepaz]

summary

• bundle the authored wolfpack-tailnet-control Markdown skill into released Wolfpack CLIs
• make the default-no interactive Pi setup copy that skill first, then install @sgtbeatdown/pi-tasks
• fail closed for existing Pi skill directories; do not install wolfpack-bridge through Pi
• document the ownership boundary and add ordering/failure regressions

verification

• bun test — 1481 pass
• bun run typecheck
• release-like compiled binary contains # Wolfpack Session Control
• security, delivery/architecture, quality, and antipattern reviews: approve / no findings