feat(kugetsu): add --debug flag for real-time output capture

- Add --debug flag to start/resume for verbose opencode output
- Use stdbuf -oL to unbuffer stdout for real-time display
- Capture debug logs to ~/.kugetsu/sessions/<id>/debug.log
- Add --debug to stop/destroy for viewing logs before actions
- Position-agnostic flag parsing (--debug can appear anywhere in args)

skills/kugetsu/scripts/kugetsu

@@ -10,28 +10,32 @@ usage() {
 kugetsu - OpenCode Session Manager
 
 Usage:
-    kugetsu start <session_id> <message>    Start a new session
+    kugetsu start <session_id> <message> [--debug]    Start a new session
-    kugetsu list [--all]                     List sessions (default: left only)
+    kugetsu list [--all]                               List sessions (default: left only)
-    kugetsu resume <session_id> [message]   Resume a session
+    kugetsu resume <session_id> [message] [--debug]   Resume a session
-    kugetsu stop <session_id>               Stop a session gracefully
+    kugetsu stop <session_id> [--debug]               Stop a session gracefully
-    kugetsu destroy <session_id> [-y]        Delete a session (prompts confirmation)
+    kugetsu destroy <session_id> [-y] [--debug]      Delete a session (prompts confirmation)
-    kugetsu destroy --all [-y]               Delete all sessions (prompts confirmation)
+    kugetsu destroy --all [-y]                        Delete all sessions (prompts confirmation)
-    kugetsu help                             Show this help
+    kugetsu help                                      Show this help
 
 States:
-    used   - Session is active (process running)
+    used    - Session is active (process running)
-    idle   - Session ended gracefully (not resumable)
+    idle    - Session ended gracefully (not resumable)
-    left   - Session interrupted/crashed (resumable)
+    left    - Session interrupted/crashed (resumable)
     invalid - Session data missing/corrupt
 
+Options:
+    --debug   Show real-time debug output and capture to debug.log
+
 Examples:
     kugetsu start mytask "fix bug #1"
+    kugetsu start mytask "fix bug #1" --debug
     kugetsu list
     kugetsu list --all
     kugetsu resume mytask
-    kugetsu resume mytask "continue working"
+    kugetsu resume mytask "continue working" --debug
-    kugetsu stop mytask
+    kugetsu stop mytask --debug
-    kugetsu destroy mytask
+    kugetsu destroy mytask --debug
     kugetsu destroy mytask -y
     kugetsu destroy --all
     kugetsu destroy --all -y
@@ -64,6 +68,37 @@ get_state() {
     fi
 }
 
+DEBUG_MODE=false
+
+set_debug_mode() {
+    DEBUG_MODE=false
+    local filtered_args=()
+    while [ $# -gt 0 ]; do
+        case "$1" in
+            --debug)
+                DEBUG_MODE=true
+                ;;
+            *)
+                filtered_args+=("$1")
+                ;;
+        esac
+        shift
+    done
+    echo "${filtered_args[@]}"
+}
+
+show_debug_log() {
+    local session_dir="$1"
+    local debug_log="$session_dir/debug.log"
+    if [ -f "$debug_log" ]; then
+        echo "=== Debug Log ==="
+        cat "$debug_log"
+        echo "=== End Debug Log ==="
+    else
+        echo "No debug log found"
+    fi
+}
+
 set_state() {
     local session_dir="$1"
     local state="$2"
@@ -100,13 +135,30 @@ check_and_update_state() {
 }
 
 cmd_start() {
-    if [ $# -lt 2 ]; then
+    local session_id=""
+    local message=""
+    
+    while [ $# -gt 0 ]; do
+        case "$1" in
+            --debug)
+                DEBUG_MODE=true
+                ;;
+            *)
+                if [ -z "$session_id" ]; then
+                    session_id="$1"
+                elif [ -z "$message" ]; then
+                    message="$1"
+                fi
+                ;;
+        esac
+        shift
+    done
+    
+    if [ -z "$session_id" ] || [ -z "$message" ]; then
         echo "Error: start requires <session_id> and <message>" >&2
         exit 1
     fi
     
-    local session_id="$1"
-    local message="$2"
     validate_session_id "$session_id"
     local session_dir=$(get_session_dir "$session_id")
     
@@ -137,7 +189,11 @@ cmd_start() {
     echo "$message" > "$session_dir/message"
     
     echo "Starting session '$session_id'..."
-    opencode run --session "$session_id" "$message"
+    if [ "$DEBUG_MODE" = true ]; then
+        stdbuf -oL opencode run --print-logs --log-level DEBUG --session "$session_id" "$message" 2>&1 | tee "$session_dir/debug.log"
+    else
+        opencode run --session "$session_id" "$message"
+    fi
     local exit_code=$?
     
     if [ $exit_code -eq 0 ]; then
@@ -184,19 +240,32 @@ cmd_list() {
 }
 
 cmd_resume() {
-    if [ $# -lt 1 ]; then
+    local session_id=""
+    local message=""
+    local args=("$@")
+    
+    for arg in "${args[@]}"; do
+        case "$arg" in
+            --debug)
+                DEBUG_MODE=true
+                ;;
+            *)
+                if [ -z "$session_id" ]; then
+                    session_id="$arg"
+                elif [ -z "$message" ]; then
+                    message="$arg"
+                fi
+                ;;
+        esac
+    done
+    
+    if [ -z "$session_id" ]; then
         echo "Error: resume requires <session_id>" >&2
         exit 1
     fi
     
-    local session_id="$1"
-    local message=""
     validate_session_id "$session_id"
     
-    if [ $# -ge 2 ]; then
-        message="$2"
-    fi
-    
     local session_dir=$(get_session_dir "$session_id")
     
     if [ ! -d "$session_dir" ]; then
@@ -251,7 +320,11 @@ cmd_resume() {
     echo "$message" > "$session_dir/message"
     
     echo "Resuming session '$session_id'..."
-    opencode run --continue --session "$session_id" "$message"
+    if [ "$DEBUG_MODE" = true ]; then
+        stdbuf -oL opencode run --print-logs --log-level DEBUG --continue --session "$session_id" "$message" 2>&1 | tee "$session_dir/debug.log"
+    else
+        opencode run --continue --session "$session_id" "$message"
+    fi
     local exit_code=$?
     
     if [ $exit_code -eq 0 ]; then
@@ -264,12 +337,27 @@ cmd_resume() {
 }
 
 cmd_stop() {
-    if [ $# -lt 1 ]; then
+    local session_id=""
+    
+    while [ $# -gt 0 ]; do
+        case "$1" in
+            --debug)
+                DEBUG_MODE=true
+                ;;
+            *)
+                if [ -z "$session_id" ]; then
+                    session_id="$1"
+                fi
+                ;;
+        esac
+        shift
+    done
+    
+    if [ -z "$session_id" ]; then
         echo "Error: stop requires <session_id>" >&2
         exit 1
     fi
     
-    local session_id="$1"
     validate_session_id "$session_id"
     local session_dir=$(get_session_dir "$session_id")
     
@@ -278,6 +366,10 @@ cmd_stop() {
         exit 1
     fi
     
+    if [ "$DEBUG_MODE" = true ]; then
+        show_debug_log "$session_dir"
+    fi
+    
     local state=$(get_state "$session_dir")
     
     if [ "$state" != "used" ]; then
@@ -322,6 +414,9 @@ cmd_destroy() {
             --all)
                 destroy_all=true
                 ;;
+            --debug)
+                DEBUG_MODE=true
+                ;;
             -y|--yes)
                 force=true
                 ;;
@@ -377,6 +472,10 @@ cmd_destroy() {
         exit 1
     fi
     
+    if [ "$DEBUG_MODE" = true ]; then
+        show_debug_log "$session_dir"
+    fi
+    
     local state=$(get_state "$session_dir")
     if [ "$state" = "used" ]; then
         echo "Error: session '$session_id' is in use (state=used)" >&2