fix: comprehensive API/UI review — 26 bug fixes and improvements

Backend:
- Scheduler lifecycle sync: create/update/delete tracker now syncs APScheduler jobs
- Test-periodic/test-memory endpoints render actual Jinja2 templates with sample data
- Cascade cleanup on tracker delete (TrackerState removed, EventLog nullified)
- Fix user_id=0 FK violation for system-owned TemplateConfig (removed FK constraint)
- Fix API key leak: only attach x-api-key header for internal provider URLs
- Validate config ownership in tracker_targets create/update
- Fix _response() double-emit of created_at in template/tracking configs
- Add per-target-link test endpoints (test, test-periodic, test-memory)

Frontend:
- Fix orphaned provider on test exception in providers/new
- Add submitting guard + disabled state to targets save button
- Move test buttons from tracker card to per-target-link rows
- Fix Svelte 5 async $state reactivity (spread reassignment for all Record mutations)
- i18n for dashboard timeAgo and event type badges (EN + RU)
- Add required attribute to chat select dropdown in targets
- Fix font CSS vars to prioritize imported DM Sans / JetBrains Mono
- Standardize empty states with centered icon + text across all 6 list pages
- Add stagger-children animation class to all list containers
- Fix slide transition duration consistency (200ms everywhere)
- Standardize border-radius to rounded-md across all form inputs
- Fix providers/new page structure (h2 + mb-8 spacing)
- Fix tracker card action row overflow (flex-wrap justify-end)
- JinjaEditor dark mode reactivity (recreate editor on theme change)
- Add aria-labels to mobile nav items
- Make ConfirmModal confirm button label/icon configurable
- Remove double error reporting on providers page
- Add telegram bot edit functionality (name editing via PUT)
- i18n for External Domain label on provider forms

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

packages/server/src/notify_bridge_server/services/notifier.py

@@ -0,0 +1,104 @@
+"""Test notification sender."""
+
+import logging
+
+import aiohttp
+
+from ..database.models import NotificationTarget
+
+_LOGGER = logging.getLogger(__name__)
+
+
+async def send_test_notification(target: NotificationTarget) -> dict:
+    """Send a simple test message to a notification target."""
+    try:
+        if target.type == "telegram":
+            return await _test_telegram(target)
+        elif target.type == "webhook":
+            return await _test_webhook(target)
+        return {"success": False, "error": f"Unknown target type: {target.type}"}
+    except Exception as e:
+        _LOGGER.error("Test notification failed: %s", e)
+        return {"success": False, "error": str(e)}
+
+
+async def _test_telegram(target: NotificationTarget) -> dict:
+    from notify_bridge_core.notifications.telegram.client import TelegramClient
+
+    bot_token = target.config.get("bot_token")
+    chat_id = target.config.get("chat_id")
+    if not bot_token or not chat_id:
+        return {"success": False, "error": "Missing bot_token or chat_id"}
+
+    async with aiohttp.ClientSession() as session:
+        client = TelegramClient(session, bot_token)
+        return await client.send_notification(
+            chat_id=str(chat_id),
+            caption="Test notification from Notify Bridge",
+        )
+
+
+async def send_test_template_notification(
+    target: NotificationTarget, slot: str, template_str: str
+) -> dict:
+    """Render a template slot with sample data and send it to a target."""
+    from jinja2.sandbox import SandboxedEnvironment
+    from ..api.template_configs import _SAMPLE_CONTEXT
+
+    if not template_str:
+        return await send_test_notification(target)
+
+    try:
+        env = SandboxedEnvironment(autoescape=False)
+        tmpl = env.from_string(template_str)
+        message = tmpl.render(**_SAMPLE_CONTEXT)
+    except Exception as e:
+        return {"success": False, "error": f"Template render error: {e}"}
+
+    try:
+        if target.type == "telegram":
+            return await _test_telegram_with_message(target, message)
+        elif target.type == "webhook":
+            return await _test_webhook_with_message(target, message)
+        return {"success": False, "error": f"Unknown target type: {target.type}"}
+    except Exception as e:
+        _LOGGER.error("Test template notification failed: %s", e)
+        return {"success": False, "error": str(e)}
+
+
+async def _test_telegram_with_message(target: NotificationTarget, message: str) -> dict:
+    from notify_bridge_core.notifications.telegram.client import TelegramClient
+    bot_token = target.config.get("bot_token")
+    chat_id = target.config.get("chat_id")
+    if not bot_token or not chat_id:
+        return {"success": False, "error": "Missing bot_token or chat_id"}
+    async with aiohttp.ClientSession() as session:
+        client = TelegramClient(session, bot_token)
+        return await client.send_notification(chat_id=str(chat_id), caption=message)
+
+
+async def _test_webhook_with_message(target: NotificationTarget, message: str) -> dict:
+    from notify_bridge_core.notifications.webhook.client import WebhookClient
+    url = target.config.get("url")
+    headers = target.config.get("headers", {})
+    if not url:
+        return {"success": False, "error": "Missing url in target config"}
+    async with aiohttp.ClientSession() as session:
+        client = WebhookClient(session, url, headers)
+        return await client.send({"message": message, "event_type": "test_template"})
+
+
+async def _test_webhook(target: NotificationTarget) -> dict:
+    from notify_bridge_core.notifications.webhook.client import WebhookClient
+
+    url = target.config.get("url")
+    headers = target.config.get("headers", {})
+    if not url:
+        return {"success": False, "error": "Missing url in target config"}
+
+    async with aiohttp.ClientSession() as session:
+        client = WebhookClient(session, url, headers)
+        return await client.send({
+            "message": "Test notification from Notify Bridge",
+            "event_type": "test",
+        })