feat(phase3): add notification system and kugetsu notify command

Phase 3c implementation - Notification System:

### New kugetsu commands:
- `kugetsu notify list` - Show unread notifications from PM Agent
- `kugetsu notify clear` - Mark notifications as read

### Notification system:
- PM Agent writes task events to ~/.kugetsu/notifications.json
- Events: task_complete, task_blocked, task_assigned
- Supports issue_ref and gitea_url for linking
- Hermes/Chat Agent reads notifications on user messages

### kugetsu-pm v2.0:
- Updated documentation with notification behavior
- PM Agent monitors Gitea for task completion
- Two review modes: PM reviews immediately OR asks dev if ready
- Notification triggers documented

### File renamed:
- phase3a-setup.md → kugetsu-chat-setup.md (more descriptive)

### Hermes gateway analysis:
- Gateway is a client (connects to Telegram), not a server
- Cannot push messages directly to Telegram from external process
- Notifications stored locally for Hermes to pick up on next user message

skills/kugetsu/scripts/kugetsu

@@ -6,6 +6,7 @@ SESSIONS_DIR="$KUGETSU_DIR/sessions"
 WORKTREES_DIR="$KUGETSU_DIR/worktrees"
 REPOS_CONFIG="$KUGETSU_DIR/repos.json"
 INDEX_FILE="$KUGETSU_DIR/index.json"
+NOTIFICATIONS_FILE="$KUGETSU_DIR/notifications.json"
 
 usage() {
     cat << 'EOF'
@@ -18,6 +19,7 @@ Usage:
     kugetsu delegate <message>                        Send message to PM agent
     kugetsu status                                    Check kugetsu initialization status
     kugetsu doctor [--fix]                            Diagnose and fix kugetsu issues
+    kugetsu notify [list|clear]                        Show or clear notifications
     kugetsu list                                     List all tracked sessions
     kugetsu prune [--force]                          Remove orphaned sessions (keeps base + pm-agent)
     kugetsu destroy <issue-ref> [-y]                  Delete session for issue
@@ -39,6 +41,8 @@ Commands:
                 PM context is loaded once at init time.
     status      Check if kugetsu is initialized and PM agent is active.
     doctor      Diagnose kugetsu issues. Use --fix to attempt repairs.
+    notify      Show or clear notifications from PM agent.
+                Use 'kugetsu notify list' to see unread notifications.
     list        Show all sessions (base + pm-agent + forked issues).
     prune       Remove sessions not in index (orphaned from opencode).
                 Use --force to skip confirmation.
@@ -52,12 +56,18 @@ PM Context:
     into the PM agent session at init time. This allows customizing PM
     behavior without recreating the session.
 
+Notifications:
+    PM Agent writes task completion notifications to ~/.kugetsu/notifications.json
+    Use 'kugetsu notify list' to see unread notifications.
+
 Examples:
     kugetsu init
     kugetsu status
     kugetsu delegate "work on issue #5"
     kugetsu doctor
     kugetsu doctor --fix
+    kugetsu notify list
+    kugetsu notify clear
     kugetsu start github.com/shoko/kugetsu#14 "fix bug"
     kugetsu continue github.com/shoko/kugetsu#14 "add tests"
     kugetsu list
@@ -305,6 +315,143 @@ kugetsu_get_pm_context() {
     fi
 }
 
+kugetsu_add_notification() {
+    local type="$1"
+    local message="$2"
+    local issue_ref="${3:-}"
+    local gitea_url="${4:-}"
+    
+    mkdir -p "$(dirname "$NOTIFICATIONS_FILE")"
+    
+    local notification=$(python3 << PYEOF
+import json
+import os
+from datetime import datetime
+
+notification = {
+    "type": "$type",
+    "message": "$message",
+    "issue_ref": "$issue_ref" if "$issue_ref" else None,
+    "gitea_url": "$gitea_url" if "$gitea_url" else None,
+    "timestamp": datetime.now().isoformat(),
+    "read": False
+}
+
+file_path = os.path.expanduser("$NOTIFICATIONS_FILE")
+notifications = []
+
+if os.path.exists(file_path):
+    try:
+        with open(file_path, 'r') as f:
+            notifications = json.load(f)
+    except:
+        notifications = []
+
+notifications.append(notification)
+
+with open(file_path, 'w') as f:
+    json.dump(notifications, f, indent=2)
+
+print("Notification added")
+PYEOF
+)
+    echo "$notification"
+}
+
+kugetsu_get_notifications() {
+    local limit="${1:-10}"
+    
+    if [ ! -f "$NOTIFICATIONS_FILE" ]; then
+        echo "[]"
+        return
+    fi
+    
+    python3 << PYEOF
+import json
+import os
+from datetime import datetime
+
+file_path = os.path.expanduser("$NOTIFICATIONS_FILE")
+
+if not os.path.exists(file_path):
+    print("[]")
+    exit(0)
+
+try:
+    with open(file_path, 'r') as f:
+        notifications = json.load(f)
+    
+    unread = [n for n in notifications if not n.get("read", False)]
+    unread.sort(key=lambda x: x.get("timestamp", ""), reverse=True)
+    
+    for n in unread[:$limit]:
+        ts = n.get("timestamp", "unknown")
+        ntype = n.get("type", "info")
+        msg = n.get("message", "")
+        issue = n.get("issue_ref", "")
+        gitea = n.get("gitea_url", "")
+        
+        print(f"[{ts}] {ntype}: {msg}")
+        if issue:
+            print(f"  Issue: {issue}")
+        if gitea:
+            print(f"  Link: {gitea}")
+        print()
+    
+    if not unread:
+        print("No unread notifications.")
+    
+except Exception as e:
+    print(f"Error reading notifications: {e}")
+PYEOF
+}
+
+kugetsu_clear_notifications() {
+    if [ ! -f "$NOTIFICATIONS_FILE" ]; then
+        return
+    fi
+    
+    python3 << PYEOF
+import json
+import os
+
+file_path = os.path.expanduser("$NOTIFICATIONS_FILE")
+
+if not os.path.exists(file_path):
+    exit(0)
+
+try:
+    with open(file_path, 'r') as f:
+        notifications = json.load(f)
+    
+    for n in notifications:
+        n["read"] = True
+    
+    with open(file_path, 'w') as f:
+        json.dump(notifications, f, indent=2)
+    
+    print("Notifications marked as read")
+except Exception as e:
+    print(f"Error: {e}")
+PYEOF
+}
+
+cmd_notify() {
+    local action="${1:-}"
+    
+    case "$action" in
+        ""|"list"|"show")
+            kugetsu_get_notifications 10
+            ;;
+        "clear")
+            kugetsu_clear_notifications
+            ;;
+        *)
+            echo "Usage: kugetsu notify [list|clear]"
+            ;;
+    esac
+}
+
 cmd_status() {
     if [ ! -f "$INDEX_FILE" ]; then
         echo "kugetsu_not_initialized"
@@ -978,6 +1125,9 @@ main() {
         doctor)
             cmd_doctor "$@"
             ;;
+        notify)
+            cmd_notify "$@"
+            ;;
         list)
             cmd_list "$@"
             ;;