fix(doctor): guard gstack find against set -euo pipefail

doctor.sh exited at the gstack-skills-count step on machines where
~/.claude/skills/gstack does not contain a skills/ subdirectory (e.g.
when the gstack submodule layout puts skills directly at root). Under
set -o pipefail, find's non-zero exit propagated through wc | tr,
killing the script before it reached the prerequisites/plugins/budget
sections.

Wrap the find in a brace group with `|| true` so the pipe stays
zero-exit and downstream sections run.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

doctor.sh

@@ -87,8 +87,10 @@ if [ -L "$HOME/.claude/skills/gstack" ]; then
   real=$(readlink -f "$HOME/.claude/skills/gstack" 2>/dev/null || readlink "$HOME/.claude/skills/gstack")
   if [ -d "$real" ]; then
     pass "Symlink OK → $real"
-    # Check for skills/ subdirectory (referenced by plugin-advisor PHASE 1)
-    gstack_skills_count=$(find "$HOME/.claude/skills/gstack/skills/" -maxdepth 1 -mindepth 1 2>/dev/null | wc -l | tr -d ' ')
+    # Check for skills/ subdirectory (referenced by plugin-advisor PHASE 1).
+    # `|| echo 0` is required because under `set -o pipefail`, a missing
+    # gstack/skills/ dir makes find exit non-zero, killing the script.
+    gstack_skills_count=$( { find "$HOME/.claude/skills/gstack/skills/" -maxdepth 1 -mindepth 1 2>/dev/null || true; } | wc -l | tr -d ' ')
     if [ "${gstack_skills_count:-0}" -gt 0 ]; then
       pass "GStack: ${gstack_skills_count} skills available"
     else