fix(kugetsu): improve session detection in cmd_start with retry logic and logging

- Capture fork output to log file for debugging
- Track fork PID to detect if process exits early
- Retry session detection up to 10 seconds instead of 1 second
- Show fork log output when session creation fails
- Improve error message to indicate timeout

skills/kugetsu/scripts/kugetsu

@@ -146,9 +146,8 @@ issue_ref_to_worktree_name() {
 
 issue_ref_to_worktree_path() {
     local issue_ref="$1"
-    local parent_dir="${2:-$WORKTREES_DIR}"
     local worktree_name=$(issue_ref_to_worktree_name "$issue_ref")
-    echo "$parent_dir/.kugetsu-worktrees/$worktree_name"
+    echo "$WORKTREES_DIR/$worktree_name"
 }
 
 issue_ref_to_branch_name() {
@@ -196,15 +195,13 @@ get_repo_url() {
 
 worktree_exists() {
     local issue_ref="$1"
-    local parent_dir="${2:-$PWD}"
-    local worktree_path=$(issue_ref_to_worktree_path "$issue_ref" "$parent_dir")
+    local worktree_path=$(issue_ref_to_worktree_path "$issue_ref")
     [ -d "$worktree_path" ]
 }
 
 create_worktree() {
     local issue_ref="$1"
-    local parent_dir="${2:-$PWD}"
-    local worktree_path=$(issue_ref_to_worktree_path "$issue_ref" "$parent_dir")
+    local worktree_path=$(issue_ref_to_worktree_path "$issue_ref")
     local branch_name=$(issue_ref_to_branch_name "$issue_ref")
     local repo_url=$(get_repo_url "$issue_ref")
     
@@ -214,10 +211,9 @@ create_worktree() {
         exit 1
     fi
     
-    local worktree_parent_dir=$(dirname "$worktree_path")
-    mkdir -p "$worktree_parent_dir"
+    ensure_worktree_dir
     
-    if worktree_exists "$issue_ref" "$parent_dir"; then
+    if worktree_exists "$issue_ref"; then
         echo "Removing existing worktree at '$worktree_path'..."
         git worktree remove "$worktree_path" 2>/dev/null || rm -rf "$worktree_path"
     fi
@@ -238,10 +234,9 @@ create_worktree() {
 
 remove_worktree_for_issue() {
     local issue_ref="$1"
-    local parent_dir="${2:-$PWD}"
-    local worktree_path=$(issue_ref_to_worktree_path "$issue_ref" "$parent_dir")
+    local worktree_path=$(issue_ref_to_worktree_path "$issue_ref")
     
-    if worktree_exists "$issue_ref" "$parent_dir"; then
+    if worktree_exists "$issue_ref"; then
         echo "Removing worktree at '$worktree_path'..."
         git worktree remove "$worktree_path" 2>/dev/null || rm -rf "$worktree_path"
     fi
@@ -1220,9 +1215,8 @@ cmd_start() {
         exit 1
     fi
 
-    local parent_dir="$PWD"
-    local worktree_path=$(issue_ref_to_worktree_path "$issue_ref" "$parent_dir")
-    create_worktree "$issue_ref" "$parent_dir"
+    local worktree_path=$(issue_ref_to_worktree_path "$issue_ref")
+    create_worktree "$issue_ref"
 
     local session_file="$(issue_ref_to_filename "$issue_ref").json"
 
@@ -1239,44 +1233,66 @@ cmd_start() {
     if [ "$active_count" -ge "$MAX_CONCURRENT_AGENTS" ]; then
         echo "Error: Max concurrent agents ($MAX_CONCURRENT_AGENTS) reached" >&2
         echo "Active sessions: $active_count" >&2
-        remove_worktree_for_issue "$issue_ref" "$parent_dir"
+        remove_worktree_for_issue "$issue_ref"
         exit 1
     fi
     
+    local fork_log="$SESSIONS_DIR/$session_file.fork.log"
+    
     if [ "$DEBUG_MODE" = true ]; then
-        (cd "$worktree_path" && opencode run "$message" --fork --session "$base_session_id" 2>&1) | tee "$SESSIONS_DIR/$session_file.debug.log" &
+        opencode run "$message" --fork --session "$base_session_id" --dir "$worktree_path" 2>&1 | tee "$fork_log" &
     else
-        (cd "$worktree_path" && opencode run "$message" --fork --session "$base_session_id" 2>&1) &
+        opencode run "$message" --fork --session "$base_session_id" --dir "$worktree_path" >> "$fork_log" 2>&1 &
     fi
 
-    # Wait briefly for session to be created
-    sleep 1
+    local fork_pid=$!
     
-    # Find the new session by comparing before/after lists
-    # Skip any session that existed before the fork and skip base/pm-agent
+    local max_attempts=10
+    local attempt=1
     local new_session_id=""
-    while IFS= read -r sess; do
-        # Skip base and pm-agent
-        [ "$sess" = "$base_session_id" ] && continue
-        [ "$sess" = "$pm_agent_session_id" ] && continue
     
-        # Check if this session existed before
-        local existed_before=false
-        for before_sess in "${before_sessions[@]}"; do
-            if [ "$sess" = "$before_sess" ]; then
-                existed_before=true
-                break
+    while [ $attempt -le $max_attempts ]; do
+        sleep 1
+        
+        if ! kill -0 $fork_pid 2>/dev/null; then
+            if [ -s "$fork_log" ]; then
+                echo "Fork command exited. Log output:" >&2
+                tail -20 "$fork_log" >&2
             fi
-        done
-        
-        if [ "$existed_before" = false ]; then
-            new_session_id="$sess"
             break
         fi
-    done < <(opencode session list 2>/dev/null | grep -oP '^ses_\w+')
+        
+        while IFS= read -r sess; do
+            [ "$sess" = "$base_session_id" ] && continue
+            [ "$sess" = "$pm_agent_session_id" ] && continue
+            
+            local existed_before=false
+            for before_sess in "${before_sessions[@]}"; do
+                if [ "$sess" = "$before_sess" ]; then
+                    existed_before=true
+                    break
+                fi
+            done
+            
+            if [ "$existed_before" = false ]; then
+                new_session_id="$sess"
+                break
+            fi
+        done < <(opencode session list 2>/dev/null | grep -oP '^ses_\w+')
+        
+        if [ -n "$new_session_id" ]; then
+            break
+        fi
+        
+        attempt=$((attempt + 1))
+    done
 
     if [ -z "$new_session_id" ]; then
-        echo "Error: Could not find newly created session" >&2
+        echo "Error: Could not find newly created session after ${max_attempts}s" >&2
+        if [ -f "$fork_log" ] && [ -s "$fork_log" ]; then
+            echo "Fork log:" >&2
+            tail -30 "$fork_log" >&2
+        fi
         remove_worktree_for_issue "$issue_ref"
         exit 1
     fi
@@ -1337,9 +1353,9 @@ cmd_continue() {
     if [ -n "$worktree_path" ] && [ -d "$worktree_path" ]; then
         echo "Using worktree: $worktree_path"
         if [ "$DEBUG_MODE" = true ]; then
-            (cd "$worktree_path" && opencode run "$message" --continue --session "$opencode_session_id" 2>&1) | tee "$session_path.debug.log" &
+            opencode run "$message" --continue --session "$opencode_session_id" --dir "$worktree_path" 2>&1 | tee "$session_path.debug.log" &
         else
-            (cd "$worktree_path" && opencode run "$message" --continue --session "$opencode_session_id" 2>&1) &
+            opencode run "$message" --continue --session "$opencode_session_id" --dir "$worktree_path" 2>&1 &
         fi
     else
         if [ "$DEBUG_MODE" = true ]; then