fix(install): build hooks/dist automatically for git clone installs

[welttowelt]

Problem

• Installing GSD from a git clone (dev flow: node bin/install.js --claude --local) often has no hooks/dist yet, so hooks silently do not install.

Fix

• If hooks/dist is missing but hooks/ exists, the installer now:
  • attempts to run scripts/build-hooks.js (if present)
  • falls back to copying gsd-check-update.js and gsd-statusline.js into hooks/dist

Result

• Hooks reliably install for both published npm tarballs and local clone installs.

Verification

• Deleted hooks/dist, ran local install, confirmed hooks end up in .claude/hooks/.