feat: add ComponentGrid and ComponentTable components for displaying components in grid and table formats

feat: implement HealthBadge and RoleBadge components for displaying health status and roles

feat: create LogViewer component for streaming logs of services

feat: develop SecretsEditor for managing secrets with CRUD operations

feat: introduce ToolCard component for displaying tool information

style: add global CSS variables and styles for consistent theming

feat: set up API client for handling requests to the backend

feat: implement hooks for fetching components, statuses, and tools

feat: create routes for dashboard, component details, and tools

feat: add service management endpoints for starting, stopping, and restarting services

feat: implement event bus for handling real-time updates via SSE

feat: create health check and logs endpoints for monitoring services

feat: add tests for health and tools endpoints to ensure functionality

chore: update project configuration files and dependencies for better development experience

castle-api/src/castle_api/stream.py

@@ -0,0 +1,71 @@
+"""SSE stream — pushes health updates and service action events to connected clients."""
+
+from __future__ import annotations
+
+import asyncio
+import json
+import logging
+import time
+
+from castle_cli.config import load_config
+
+from castle_api.config import settings
+from castle_api.health import check_all_health
+
+logger = logging.getLogger(__name__)
+
+# All connected SSE clients receive events through this queue-based broadcast.
+_subscribers: list[asyncio.Queue[str]] = []
+
+
+def subscribe() -> asyncio.Queue[str]:
+    """Register a new SSE client. Returns a queue to read events from."""
+    q: asyncio.Queue[str] = asyncio.Queue(maxsize=64)
+    _subscribers.append(q)
+    return q
+
+
+def unsubscribe(q: asyncio.Queue[str]) -> None:
+    """Remove a disconnected SSE client."""
+    try:
+        _subscribers.remove(q)
+    except ValueError:
+        pass
+
+
+def close_all_subscribers() -> None:
+    """Unblock all SSE generators so they exit during shutdown."""
+    for q in list(_subscribers):
+        try:
+            q.put_nowait("")
+        except asyncio.QueueFull:
+            pass
+    _subscribers.clear()
+
+
+async def broadcast(event_type: str, data: dict) -> None:
+    """Send an event to all connected SSE clients."""
+    payload = f"event: {event_type}\ndata: {json.dumps(data)}\n\n"
+    dead: list[asyncio.Queue[str]] = []
+    for q in _subscribers:
+        try:
+            q.put_nowait(payload)
+        except asyncio.QueueFull:
+            dead.append(q)
+    for q in dead:
+        unsubscribe(q)
+
+
+async def health_poll_loop(interval: float = 10.0) -> None:
+    """Background task that polls health and broadcasts updates."""
+    while True:
+        try:
+            config = load_config(settings.castle_root)
+            statuses = await check_all_health(config)
+            await broadcast("health", {
+                "statuses": [s.model_dump() for s in statuses],
+                "timestamp": time.time(),
+            })
+        except Exception:
+            logger.exception("Health poll failed")
+        await asyncio.sleep(interval)