fix(clv2): use -e instead of -d for .git check in detect-project.sh

In git worktrees, .git is a file (not a directory) containing a gitdir
pointer. The -d test fails for worktree checkouts, causing project
detection to fall through to the "global" fallback. Changing to -e
(exists) handles both regular repos and worktrees correctly.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

skills/continuous-learning-v2/scripts/detect-project.sh

@@ -85,7 +85,7 @@ _clv2_detect_project() {
   # fall back to path hash (machine-specific but still useful)
   local remote_url=""
   if command -v git &>/dev/null; then
-    if [ "$source_hint" = "git" ] || [ -d "${project_root}/.git" ]; then
+    if [ "$source_hint" = "git" ] || [ -e "${project_root}/.git" ]; then
       remote_url=$(git -C "$project_root" remote get-url origin 2>/dev/null || true)
     fi
   fi