fix: use main worktree path for all path calculations

When running commands from inside a worktree, several functions
incorrectly used the current worktree's path instead of the main
worktree's path for calculating directories and finding config files.

Fixed functions:
- _wt_find_worktree: worktree lookup now works from any worktree
- _wt_new: creates worktrees in correct location from any worktree
- _wt_up/_wt_down: finds .cursor/worktrees.json in main worktree

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: jorgensandhaug

wt.sh

@@ -273,10 +273,12 @@ _wt_new() {
     return 1
   fi
 
+  local main_worktree
+  main_worktree=$(_wt_get_main_worktree)
   local base_name
-  base_name=$(_wt_get_base_name "$repo_root")
+  base_name=$(basename "$main_worktree")
   local parent_dir
-  parent_dir=$(dirname "$repo_root")
+  parent_dir=$(dirname "$main_worktree")
 
   local branch_name
   local worktree_path
@@ -371,10 +373,10 @@ _wt_new() {
     fi
   fi
 
-  _wt_run_setup_commands "$repo_root" "$worktree_path"
+  _wt_run_setup_commands "$main_worktree" "$worktree_path"
 
   if [[ "$run_up" == true ]]; then
-    _wt_run_up_commands "$repo_root" "$worktree_path"
+    _wt_run_up_commands "$main_worktree" "$worktree_path"
   fi
 
   cd "$worktree_path" || return 1
@@ -396,7 +398,9 @@ _wt_up() {
     return 1
   fi
 
-  _wt_run_up_commands "$repo_root" "$repo_root"
+  local main_worktree
+  main_worktree=$(_wt_get_main_worktree)
+  _wt_run_up_commands "$main_worktree" "$repo_root"
 }
 
 _wt_down() {
@@ -407,7 +411,9 @@ _wt_down() {
     return 1
   fi
 
-  _wt_run_down_commands "$repo_root" "$repo_root"
+  local main_worktree
+  main_worktree=$(_wt_get_main_worktree)
+  _wt_run_down_commands "$main_worktree" "$repo_root"
 }
 
 _wt_ls() {
@@ -461,12 +467,12 @@ _wt_find_worktree() {
     return 1
   fi
 
-  local base_name
-  base_name=$(_wt_get_base_name "$repo_root")
-  local parent_dir
-  parent_dir=$(dirname "$repo_root")
   local main_worktree
   main_worktree=$(_wt_get_main_worktree)
+  local base_name
+  base_name=$(basename "$main_worktree")
+  local parent_dir
+  parent_dir=$(dirname "$main_worktree")
 
   # Check if name matches main worktree
   if [[ "$name" == "$base_name" ]] || [[ "$name" == "main" ]]; then